JPH0457725A - Method and device to obtain packaged body by cutting film around tray - Google Patents

Abstract

PURPOSE:To obtain a beautiful appearance by a method wherein a film is placed over a tray filled with an object to be packaged, and the film is brought into contact with the outer periphery of the tray, and a heating element is moved toward the central direction from the outer surrounding and brought into pressure-contact with the outer periphery of the tray or film, and at the same time, the periphery of the film is pulled downward, and the periphery of the film is welded at the lower end of the pressing surface or on the contact line. CONSTITUTION:On a tray l filled with an object to be packaged, a film 2 which is let out from a film roll 37 through guide rollers 38, 39 and letting out rollers 40, 41 is stretched. Then, while pulling the periphery of the film 2 downward by a holding plate frame B, the film 2 is brought into contact with the outer periphery of the tray l to wrap the tray l. Then, with the outer periphery of the tray l, a heating element frame A is brought into pressure-contact, by contracting the heating element frame A toward the central direction of the tray l from the outer surrounding. By doing this, the periphery of the film 2 is welded at the lower end of a pressing surface 5 between the heating element frame A and the tray outer periphery.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to the general field of wrapping trays containing items to be packaged with a film, and particularly to cutting the film around the tray when packaging food products. The present invention relates to a method for obtaining a package and an apparatus used in the method.

[Conventional technology]

The conventional method of cutting the top film around the tray is, for example, a method called top seal, in which the top film is glued to the flange surface of the tray, which has a flat flange around the periphery, and then punched out in one piece with a punching blade or the like. It had been removed.

In addition, in the device devised by the present applicant (described in Japanese Utility Model Publication No. 55-49521), the heat-softened upper film is molded in close contact with the outer surface of the tray and the heating element (chrome wire, etc.), and then the heating element generates heat. It was fused due to

[Problem to be solved by the invention]

All of these conventional devices have film cutting means such as punching blades or heating elements fixed to a fixed tray shape, and cannot be used for trays of other shapes. Therefore, when changing the shape of the tray, the entire cutting device must be replaced, which requires very complicated work and significantly reduces productivity.

Furthermore, in the apparatus disclosed in Japanese Utility Model Publication No. 55-49521, the peripheral edge of the fused film hangs down from the lower end of the outer periphery of the tray, and the appearance of the apparatus was not good enough.

[Means to solve the problem]

In order to solve the above-mentioned drawbacks, the method of the present invention overlaps a tray with items to be packaged with a film, brings the film into contact with the outer periphery of the tray, and moves the heating element from the outer periphery of the tray toward the center. , the process of bringing the film into pressure contact with the outer periphery of the tray or the film, simultaneously pulling the periphery of the film downward, and fusing the periphery of the film at the lower end of the pressing surface or on the contact line.

Further, the device of the present invention has a heating element rectangular frame (A) formed with two sets of rod-shaped heating elements or plate-shaped heating elements that are arranged facing each other so as to be able to approach and separate from each other, and whose inner area can be enlarged and contracted. A holding plate rectangular frame (B) formed of two sets of holding plates arranged facing each other so as to be able to be separated so that the area inside the frame can be enlarged and reduced, and capable of operating independently below the heating element rectangular frame (A); The configuration has the following.

[Effect]

The method of the present invention described above makes it possible to package trays of different sizes and shapes with the same means, and furthermore,
Since the film can be cut by melting at the lower end of the outer circumferential surface of the tray or on the outer circumferential side surface, it has become possible to create beautiful packaging in which excess film does not hang down on the side surface of the tray.

Although the method and device of the present invention can also be used to cut the film at a position where it hangs down from the lower edge of the outer periphery of the tray, in such a cutting method, all the effects of the present invention cannot be utilized. It means that it is not.

In addition, in the apparatus of the present invention, the heating element frame and the holding plate frame are configured so that the area inside the frame can be enlarged or reduced by a simple operation, so that trays of different shapes can be wrapped in film with a simple configuration.

〔Example〕

First, the present invention will be explained in detail using No. 1 (a) to (b).

Place the film roll (
37) through the guide rollers (38) (39) and the feed rollers (40) (41). ), the periphery of the film (2) is pulled downward by the holding plate frame CB), and the film (2) is brought into contact with the outer periphery of the tray (1) so as to overlap. ) as shown in this tray (1)
The heating element frame (A) is contracted and pressed into contact with the outer periphery of the tray (1) from the outer periphery toward the center of the tray (1). Then, the periphery of the film (2) is cut by melting at the lower end of the pressing surface (5) around the outside of the tray. At this time, if only the holding plate frame (B) is further reduced and the periphery of the film (2) is further pulled downward, the film (2) can be more easily cut by fusing.

Further, while carrying out the cutting method described above, it is also possible to heat-seal the film to the tray at the outer periphery of the tray using the pressure of a heating element at the same time, and it is also possible to provide a sealing method together with the cutting method.

The method of the present invention basically consists of the above steps,
Repeat the above steps (a) to (→) to wrap the tray in film.Basically, by appropriately changing the movement of frames (A) and (B), more complete cutting can be achieved. In other words, although Fig. 1 shows an example in which the rectangular frame (A) of the heating element is moved horizontally and pressed, it may also be pressed while being lowered slightly. The body may also not be flat but may be inclined or curved to match the shape of the tray and provide a satisfactory pressing force.

If the film (2) is heated and softened before packaging, the adhesion and adhesion between the tray (1) and the film (2) will improve, but it is recommended to use a material that is flexible enough even at room temperature, such as stretch film. This step is not particularly necessary when used, and the same effect can be obtained by applying glue (6) to the outer peripheral edge of the tray as shown in Fig. 2 (a) Φ) (C). but a sufficiently adhesive combination, e.g. PVC
) If a single or composite film having a tray coated with PVDC or a PVDC layer and an EVA layer on the bottom surface of the film is used, there is no need to apply glue.

Generally, in the case of a flat heating element as shown in Fig. 4, the film is fused at a point in the middle of Fig. 3(a) at the outer peripheral edge of the tray (5), but this is shown in Fig. 3(a). When the heating element frame (A) is pressed against the tray flange as shown in Fig. 3 (6)
The heat applied to points E and F of the tray diffuses into the tray fabric and escapes, whereas the heat applied to point D has no place to diffuse and escape, causing the heat to be concentrated more than other parts and melting the film. Because point temperature is reached in a short time and point D is pressed most strongly against the heating element frame (A), when the film (2) is pulled downward as shown in the figure It is thought that the film (2) is cut at point D.

Moreover, when the frame (B) is enlarged and pulled downward as shown in FIG. 3C, the heating element frame (A) is cut at the lower end G.

Further, in the case of a heating element frame as shown in FIGS. 9 and 10, the heating element is cut at the contact line between the heating element and the film. This is true whether the contact line is on the outer periphery of the tray or in a position hanging down from the outer periphery.

In this example, a PSP trench film is used as the film, a PSP tray having the shape shown in FIG. 2(b) is used as the tray, and the film and tray are glued together. Other tray materials include OPS, HI, PVC,
PET etc. can be used.

In addition, the heat resistance of PSP used for the tray fabric is about 70°C, while a heating element temperature of 130°C is required to melt the PVC stretch film. PSP by adjusting the time
You can cut the fabric beautifully without damaging it.

Next, the apparatus of the present invention will be explained.

The device of the present invention has a heating element frame (A) that fuses the film, and a holding plate frame (B) that pulls the film downward to make the upper film taut and also serves as an auxiliary function for the film melting. Each frame is characterized by a structure in which the area within the frame can be expanded or contracted independently and in some cases in conjunction with each other without interfering with mutual movement.

First, a first embodiment of the apparatus of the present invention will be described with reference to FIGS. 4 to 8. The heating element frame (A) has two opposing sides of the frame formed by side heating walls (14) arranged oppositely,
The remaining two sides are composed of a front heat generating wall (15) and a back heat generating wall (16) which are arranged to face each other.

The side heat generating wall (14) consists of a flat plate (13) divided into a large number of strips each having a heat generating element (4) embedded therein, and each of which is connected to an attachment (11) of a roller link plate (11).
The chain (10) fixed to the chain (12) and this chain (
Sprocket (8) (9) with both ends of 10) wound and fixed
and a rotating shaft (17) (1B) for rotating the sprockets (8) and (9) in forward and reverse directions.
The two opposing sides have the same configuration.

(8) and (9) are the rotating shafts (17) and (1).
8) are rotated forward and reverse by interlocking the left and right sides using a manual handle or forward/reverse motor, etc., and thereby the lengths of the side heat generating walls (14) on both sides can be adjusted to create trays (1) of various sizes. I am trying to make it match.

The flat plate (13) is made of a material with good thermal conductivity, such as aluminum or copper, and has a heating element (4) embedded in its flat surface that contacts the packaging tray. This heating element (4) uses a nichrome wire or the like, and subsequent heating elements also use similar resistance wires.

The side heat generating wall (14) has the above structure, and this structure is exactly the same on two opposing sides.

As mentioned above, the remaining two sides of the heating element frame (A) are composed of the front heating wall (15) and the back heating wall (16), which are made of aluminum, copper, etc., in which the heating element (4) is embedded. It is constructed by arranging long flat plates (7) with good thermal conductivity in parallel and facing each other. This front and back heating wall (15) (16
) has a structure that can be freely approached and separated in opposing directions.

Further, the above-mentioned flat plate (13) and long flat plate (7) may be provided with fine grooves in the areas where they come into contact with the tray to prevent the molten film from sticking.Also, it is better to apply a Teflon coat to the surface. becomes.

Next, a columnar corner heating element (21) with a roughly triangular cross section
Place at the four corners of the rectangular frame. This corner heating element (21) is made of aluminum, copper, etc., and has a triangular cross section with one side being a straight line and the remaining two sides concave in an arc shape toward the center, with the flat part facing the front or back. One arc-shaped concave surface is in contact with the heat-generating walls (15) and (16), and is in contact with the side heat-generating wall (14), which is wound around the sprockets (8) and (9) to form an arc, and the remaining arc-shaped concave surfaces The heating element (4) is buried, and the tray corner is cut by fusing. This corner heating element (2
1) is attached so as to be slidable along the longitudinal direction of the front and rear heat generating walls (15) and (16). Note that the corner heating element (21) may be replaced with one that matches the radius shape of the corner of the tray so that it can be attached.

The flat plate (13), the long flat plate (7), and the corner heating element (21) are made of aluminum or the like, and the heating element (4) is buried inside the plate as shown in FIG. The structure is such that the entire section generates heat. The buried heating element (4) is connected to a power source with an electric wire (not shown), and has a structure that generates heat at the same time when electricity is applied.

Next, an example of the structure of the holding plate frame (B) will be explained with reference to FIG. There are various possible structures and ways of moving the holding frame, but for the sake of convenience, I will explain it in an easy-to-understand way, for example:
Four rods (22) to which a holding plate (3) made of heavy material such as metal is fixed to the center are assembled in a frame shape, and corner pieces (23) are attached to the corners of the rods so as to be slidable. It is constructed by inserting it. By manually or automatically moving the corner pieces (23) toward and away from each other, the area within the frame can be expanded or contracted, thereby allowing trays (1) of various sizes to be formed.
It can be applied to

This holding plate frame (B) is arranged below the heating element frame (A), and the interval therebetween can be adjusted according to the height of the tray. The plate frames (B) do not interfere with each other's movement, but have a structure that allows them to move independently. Not only horizontally,
It would be better if it could also be operated in the vertical direction.

A second embodiment of the device of the present invention will be described with reference to FIG.

This embodiment replaces the heating element frame (A) of the first embodiment with a heating element (4
) with embedded thin aluminum plate (24) (25
), and the holding plate frame (B) uses the same device as in the first embodiment.

The thin flat plates (24) and (25) are made of a material with good thermal conductivity such as aluminum, and have heating elements (4) along their long sides.
bury it. Two thin flat plates (24) are arranged in parallel to face each other, and are connected to a front heat generating plate (26) and a rear heat generating plate (26).
7), two thin flat plates (25) in which the heating element (4) is embedded in the same way are arranged in parallel to face each other, and this is called a side heating plate (28χ), and a corner piece is placed in a part of these corners. (29) is slidably inserted to constitute the heating element frame (A).

A thin flat plate (24) perpendicular to the corner piece (29)
(25) are fitted with a fit that does not prevent mutual sliding, and the guide grooves (30) formed on the upper surfaces of the thin flat plates (24) and (25) and the corner pieces (2
9) The protrusion (31) protruding inside fits and slides smoothly. There are also four corner pieces (29
) can be manually or automatically moved in parallel with the four heat generating plates to enlarge or reduce the area within the heat generating frame (A).

Note that the method of embedding the heating element (4) and the method of electrical connection may be the same as in the first embodiment.

A third embodiment of the device of the present invention will be described with reference to FIGS. 10(a) and (b). Similar to the second embodiment described above, this embodiment differs only in the heating element frame (A) of the first embodiment, and the retaining plate frame (B) is the same as in the first embodiment. Use the equipment.

The heating element frame (A) of the third embodiment is formed by directly assembling the rod-shaped heating elements themselves into a rectangular shape.
The structure is exactly the same as the second embodiment except that a rod-shaped heating element is used instead of the flat plate in which the heating element is embedded. That is, the front heating element (32) and the back heating element (33)
), side heating elements (34) (34), and a corner piece (35) slidably inserted into a part of these corners. Each corner piece (35) has two orthogonally intersecting circular holes formed therethrough to form orthogonal heating elements (32) (34).
Alternatively, (33) and (34) can be slidably inserted in parallel to each of the four heating elements (23), (33), and (34) on a horizontal surface. The corner piece (35) can be slid manually or automatically to enlarge or reduce the area within the frame of the heating element frame (A) of this embodiment.

〔Effect of the invention〕

According to the method of the present invention, it is possible to wrap various types of film with the same method regardless of the material, thickness, etc. of the synthetic resin film, and even with various shapes around the outside of the tray. The film will form a straight line, eliminating any drooping of the excess film, resulting in a beautiful appearance.

Furthermore, according to the device of the present invention, continuous film packaging is possible by adjusting the frame to match the tray shape, and even when changing the tray shape midway through, the frame can be adjusted with a simple operation. This makes it possible to improve productivity.

[Brief explanation of the drawing]

Figures 1 (a) to (4) are explanatory diagrams of the operational sequence showing the method of the present invention; Figures 2 (4), (c), and (C) are sectional views of essential parts showing various parts to which the present invention can be applied; The figure is a schematic perspective view of the first embodiment of the heating element frame of the device of the present invention, FIG. 5 is a plan view of essential parts of the first embodiment of the device of the present invention, and FIG. FIG. 7 is a cross-sectional view showing an example of embedding the heating element, FIG. 8 is a perspective view of the holding plate frame of the device of the present invention, and FIG. 9 is a perspective view of the heating element frame of the device of the present invention. A perspective view of the second embodiment, FIG. 9a is a cross-sectional view taken along the line CC in FIG. FIG.
...Tray (2) -Film, (3)...
・-・Holding plate, (4) -heating element, (5)-m-・
Tray outer peripheral edge. Figure 1

Claims (2)

[Claims] (1) Wrap the film over the tray on which the items to be packaged are placed, and bring the film into contact with the outer periphery of the tray. Move the heating element from the outer periphery of the tray toward the center, and then touch the film to the outer periphery of the tray or the film. A method for cutting a film around a tray to obtain a package, comprising the steps of simultaneously bringing the film into pressure contact, pulling the film downward, and fusing the film around the lower end of the pressing surface or on the contact line. (2) A heating element frame formed by rod-shaped heating elements or plate-shaped heating elements arranged facing each other so as to be able to approach and separate from each other so that the area inside the frame can be expanded and contracted, and a frame consisting of retaining plates that are arranged facing each other so as to be able to approach and separate from each other. The film around the tray according to claim (1), further comprising a holding plate frame whose inner area can be enlarged and reduced and which can be operated independently below the heating element rectangular frame. A device used to cut and obtain packaging.