Shrink wrapping machine

Abstract

To provide a shrink package device which can form a film easy break line by perforation on a shrink film of a shrink film package article without breaks on heating and in a form of facilitating taking-out of the article.SOLUTION: A perforation formation device 15 for providing a film easy break line 54 on one face of a shrink package article 50 of a hexagonal shape after shrink packaging includes a disc-formed round knife 16 equipped with a plurality of projection cutter blades 16a arranged circumferentially at intervals. This round knife 16 is provided with a plurality of projection cutter blades 16a in continuity only at a part in a circumferential direction, only in a virtual straight line 53 traversing one face of the shrink package article 50, so that a plurality of unit perforations 52a constituting a perforation 52 may be formed in continuity at 5 to 22 points at intervals S of 1.0 to 7.0 mm with a length of 0.5 to 1.5 mm.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a shrink packaging device for shrink packaging an article having a hexahedral shape, such as a booklet, with a shrink film having heat shrinkability.

Background Art

[0002] Conventionally, as a form of packaging various articles such as cup noodles, shrink packaging using a shrink film, which is a film made of a synthetic resin having heat shrinkability, is known. Shrink packaging is obtained by forming a shrink film provided with pinholes on the film surface into a tubular shape, accommodating an article inside the formed tubular shrink film, and sealing both ends. The article accommodation bag thus obtained is heated by passing it through a heating unit to shrink the shrink film, so that the article can be packaged with the shrink film closely attached to the surface. Various packaging devices for performing such shrink packaging have been developed (for example, see Patent Document 1).

[0003] The shrink packaging device described in Patent Document 1 includes an article supply unit for supplying an article, a film supply unit for supplying a shrink film, an article accommodation unit for accommodating the article in a bag made of the shrink film to form an article accommodation bag, a heating unit for heating the formed article accommodation bag, etc. When passing the article accommodation bag through the heating unit, the shrink film is heated, and by the synergistic action of the shrinkage of the shrink film and the air inside the article accommodation bag being once heated and expanded and then discharged from the pinholes, a shrink packaged article in which the shrink film is closely attached to the surface and the article is packaged can be obtained.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] On the other hand, with the diversification of sales methods for goods in recent years, there has been consideration of shrink-wrapping items with a hexahedral shape, such as booklets formed by laminating multiple printed sheets of paper with a rectangular planar shape to a predetermined thickness, using shrink film.

[0006] Furthermore, when shrink-wrapping an article with a hexahedral shape, the heat-shrunk shrink film will adhere tightly to all six sides of the hexahedral article. Therefore, it is expected that removing the tightly adhering shrink film from the shrink-wrapped hexahedral package and taking out the article will require considerable effort. For this reason, it is conceivable to make it easier to remove the article by providing an easy-tear line, such as a perforation, on one of the sides of the hexahedral shape of the shrink film covering the hexahedral article.

[0007] However, when a perforated line for easy tearing is provided on one of the faces of a hexahedral-shaped shrink film covering a hexahedral-shaped article, the perforations must be formed in the shrink film prior to heating in the heating section. Depending on the form of the formed perforations, it is anticipated that the perforated line may break when the air inside the article-containing bag expands due to heating during heating, or that it may become difficult to find or tear the film's easy tear line when removing the shrink film from a hexahedral-shaped shrink-wrapped article to take out the article. For this reason, there is a need for the development of a device that can solve the unique technical challenges associated with such hexahedral-shaped shrink-wrapped articles.

[0008] The present invention aims to provide a shrink packaging apparatus that enables the easy formation of perforations, which serve as easy-tear lines, on the shrink film of any of the hexahedral surfaces of a hexahedral shrink film packaged article covered with shrink film, in a manner that prevents tearing during heating and facilitates tearing when removing the article. [Means for solving the problem]

[0009] The present invention relates to a shrink packaging apparatus comprising: an article supply unit for supplying articles having a hexahedral shape; a film supply unit for supplying heat-shrinkable shrink film; an article storage unit for storing the articles in a storage unit made of shrink film to form an article storage bag before heat shrinking; and a heating unit for shrink packaging the stored articles by heating the formed article storage bag to heat shrink the shrink film, wherein the film supply unit has perforations formed along the supply direction of the shrink film to provide an easy-tear line on one side of the hexahedral shrink-packaged article after shrink packaging. The above objective is achieved by providing a shrink packaging device that includes a perforation forming device, which includes a disc-shaped round knife equipped with a plurality of protruding cutter blades arranged at intervals in the circumferential direction, wherein the plurality of protruding cutter blades are arranged in a continuous manner only in a portion of the circumferential direction, so that a plurality of unit perforations constituting the diaphragm are formed in a continuous manner at intervals of 1.0 to 7.0 mm and with a length of 0.5 to 1.5 mm in only a portion of a hypothetical straight line crossing one surface of the shrink-wrapped article at 5 to 22 locations.

[0010] Furthermore, it is preferable that the shrink packaging device of the present invention has multiple protruding cutter blades arranged in a continuous manner only on a portion of the circumferential direction, such that multiple unit perforations constituting the diaphragm are formed by arranging 6 to 15 such perforations in a continuous manner at intervals of 3.0 to 6.5 mm with a length of 0.5 to 1.0 mm.

[0011] Furthermore, it is preferable that the shrink packaging apparatus of the present invention is configured such that the round knife of the perforation forming apparatus forms the perforations with a plurality of protruding cutter blades while rotating with the shrink film sandwiched between the round knife and the rotating roller around which the shrink film is wound.

[0012] Furthermore, it is preferable that the shrink packaging apparatus of the present invention includes a reciprocating mechanism that moves the round knife forward and backward relative to the rotating roller.

[0013] Furthermore, it is preferable that the shrink packaging device of the present invention is such that the article having the hexahedral shape is a booklet formed by laminating a plurality of printed sheets having a rectangular planar shape to a predetermined thickness. [Effects of the Invention]

[0014] According to the shrink packaging apparatus of the present invention, perforations that serve as easy-tear lines for the film can be easily formed on any of the faces of a hexahedral shrink film packaged article covered with shrink film, in a manner that prevents tearing during heating and makes it easy to tear when removing the article. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic side view illustrating the configuration of a shrink packaging apparatus according to a preferred embodiment of the present invention. [Figure 2] This is an enlarged view of section A in Figure 1, illustrating the process of forming perforations in shrink film using a perforation forming device. [Figure 3] (a) is a front view illustrating a circular knife, and (b) is a cross-sectional view of (a) along line BB. [Figure 4] (a) is a schematic perspective view illustrating a shrink-film packaged article formed by a shrink-wrapping device, and (b) is a front view of the said shrink-film packaged article. [Figure 5]This is an enlarged schematic side view illustrating the first heating tunnel that constitutes the heating section. [Figure 6] This is an enlarged schematic side view illustrating the second heating tunnel that constitutes the heating section. [Figure 7] This is an enlarged schematic side view illustrating the goods supply section. [Modes for carrying out the invention]

[0016] The shrink packaging apparatus 10 shown in Figure 1, according to a preferred embodiment of the present invention, is used as an apparatus for forming a hexahedral shrink film packaged article 50 (see Figure 4) by covering a booklet 50', which is formed by laminating a plurality of printed sheets having a rectangular planar shape to a predetermined thickness, with a shrink film 20. The shrink packaging apparatus 10 of this embodiment easily forms perforations 52, which serve as easy-tear lines 54, on the shrink film 20 covering, for example, one side of the hexahedral shrink film packaged article 50', in a manner that does not tear during heating, but makes it easy to tear when removing the booklet 50', thereby ensuring that the resulting shrink film packaged article 50' is distributed and sold in a stable packaged form, and that the booklet 50' can be smoothly removed when in use.

[0017] And the shrink packaging device 10 of this embodiment includes an article supply unit 11 that supplies a booklet 50' before packaging, which is an article having a hexahedral shape, a film supply unit 12 that supplies a shrink film 20 having heat shrinkability, an article accommodation unit 13 that accommodates the booklet 50' in an accommodation portion formed by the shrink film 20 to form an article accommodation bag 51 before heat shrinkage, and a heating unit 14 that heats the formed article accommodation bag 51 to heat-shrink the shrink film 20, thereby shrink-packaging the accommodated booklet 50' into a shrink film-packaged article 50. A perforation forming device 15 is disposed in the film supply unit 12 to form perforations 52 (see FIG. 4) along the supply direction of the shrink film 20, so as to provide a film easily breakable line 54 on one surface of the hexahedral shrink film-packaged article 50 after shrink packaging. As shown in FIGS. 2 and 3(a) and (b), the perforation forming device 15 includes a disk-shaped round knife 16 provided with a plurality of protruding cutter blades 16a arranged at intervals in the circumferential direction. On only a part of a virtual straight line 53 (see FIG. 4) that crosses one surface of the shrink film-packaged article 50, a plurality of unit perforations 52a constituting the perforations 52 are continuously formed at 5 to 22 locations with a length L of 0.5 to 1.5 mm and an interval S of 1.0 to 7.0 mm. Accordingly, the plurality of protruding cutter blades 16a are continuously provided only on a part of the circumferential direction (see FIG. 3(a)).

[0018] Also, in this embodiment, the round knife 16 of the perforation forming device 15 is configured to form the perforations 52 by the plurality of protruding cutter blades 16a while rotating with the shrink film 20 sandwiched between the round knife 16 and a rotating roller 17 around which the shrink film 20 is wound (see FIG. 2).

[0019] Furthermore, in this embodiment, the perforation forming device 15 includes an advancing and retreating mechanism 18 that advances and retreats the round knife 16 with respect to the rotating roller 17.

[0020] In this embodiment, the shrink packaging device 10 has the same configuration as the shrink packaging device described in Patent Document 1 above, except that, for example, a perforation forming device 15 is provided, the heating unit 14 includes a first heating tunnel 25 and a second heating tunnel 26 as will be described later, and the article supply unit 11 supplies the booklet 50'.

[0021] That is, as described above, the shrink packaging device 10 of this embodiment includes an article supply unit 11, a film supply unit 12, an article storage unit 13, and a heating unit 14, and also includes a moving means 19 composed of a supply conveyor 19a, a feed conveyor 19b, and a discharge conveyor 19c, a defective product automatic removal device 21, an operation panel 22, a scrap winding device, and the like.

[0022] As shown in FIG. 7, the article supply unit 11 includes a booklet hopper unit 11a that can stack and hold a plurality of hexahedral booklets 50' placed flat, and an extrusion piston 11c that is disposed at the lower part of the booklet hopper unit 11a so as to be able to advance and retreat and extrude the lowermost booklet 50' into the sandwich conveyance unit 11b one by one. The booklet 50' extruded by the extrusion piston 11c is sandwiched between an upper pressing belt 11d and a lower pressing belt 11e that rotate endlessly in the sandwich conveyance unit 11b, and can be sequentially sent out to the supply conveyor 19a (see FIG. 1) of the moving means 19.

[0023] As shown in FIG. 1, the film supply unit 12 includes a film holder 12a formed by winding a shrink film 20 multiple times around a rotating shaft, and a plurality of guide rollers 12b that guide the shrink film 20 continuously drawn out in a strip shape from the film holder 12a toward the article storage unit 13. A known film splicer 12c, a perforation forming device 15 described later, and a known pinhole forming device (not shown) are disposed in a part of the supply path by the guide rollers 12b that constitute the film supply unit 12.

[0024] The article storage section 13 is a known structure that includes a sealing section 13a, a side sealing section 13b, a horizontal sealing section 13c, etc. The sealing section 13a is the part that encloses the booklet 50', which is a hexahedral article, inside the shrink film 20 that is continuously supplied in a strip from the film supply section 12, while folding it back in the width direction. The shrink film 20 that encloses the booklet 50' in the sealing section 13a is sealed at the folded open side by the side sealing section 13b on the downstream side in the supply direction, forming a cylindrical shape containing the booklet 50', and after being sent to the supply conveyor 19b, the horizontal sealing section 13c further seals both the front and rear ends in the supply direction that sandwich the contained booklet 50'. This creates an article storage bag 51 before heat shrinkage, in which the booklet 50' is sealed and stored in the bag-shaped storage section made of the shrink film 20. The formed article storage bag 51 is then fed via the discharge conveyor 19c to the heating section 14, which consists of the first heating tunnel 25 and the second heating tunnel 26 on the downstream side in the supply direction.

[0025] In this embodiment, a perforation forming device 15 is provided in the film supply unit 12 to form perforations 52 along the supply direction of the shrink film 20, thereby providing a film break-off line 54 on one side of the hexahedral shrink-packaged article 50 after shrink packaging (see Figure 4). As shown in an enlarged view in Figure 2, the perforation forming device 15 includes a rotating shaft box 15a to which a round knife 16 is attached, a sliding support column 15b that supports the rotating shaft box 15a so that it can slide up and down, and a rotating roller 17 that is supported by the sliding support column 15b and positioned directly below the rotating shaft box 15a.

[0026] A rotating shaft box 15a has a rotating shaft 15c mounted at its lower part, to which a removable round knife 16 is fixed in a predetermined axial position, in a rotatably supported manner. Inside the rotating shaft box 15a, a rotational drive mechanism 15e is provided for rotationally driving the rotating shaft 15c via a rotating belt 15d, and the rotational speed can be controlled by operating the control panel 22 (see Figure 1). A sliding mechanism 18 is integrally mounted on the upper part of the rotating shaft box 15a, extending toward the sliding column 15b side and functioning as a reciprocating mechanism 18 that moves the round knife 16 fixed to the rotating shaft 15c forward and backward relative to the rotating roller 17, and is slidable vertically along the sliding column 15b. The sliding mechanism 18 can be automatically controlled by operating the control panel 22 to intermittently move the round knife 16 up and down at predetermined timings.

[0027] In this embodiment, the round knife 16 fixed to the rotating shaft 15c is a plate-like member having a disc shape made of metal or synthetic resin, as shown in Figures 3(a) and (b). The round knife 16 has a disc shape with a diameter of approximately φ50 mm, and a circular fixing opening 16c is formed in the central part, with an inner diameter of approximately φ15 mm and a locking notch 16b cut out on the outside for fixing the round knife 16 to the rotating shaft 15c in a non-rotatable manner. The round knife 16 has multiple protruding cutter blades 16a arranged in a continuous manner in the circumferential direction, for example in a region of approximately 120° in the circumferential direction, with a circumferential arc length L' of approximately 0.5 to 1.5 mm and a circumferential arc spacing S' of approximately 1.0 to 7.0 mm, protruding at 5 to 22 locations, preferably with a protrusion height of approximately 2 mm. More preferably, the blades are provided in a continuous configuration in the circumferential direction, with a circumferential arc length L' of about 0.5 to 1.0 mm and a circumferential arc spacing S' of about 3.0 to 6.5 mm, protruding at 6 to 15 locations, preferably with a projection height of about 2 mm. In addition, the circumferential arc length M' of the connected tips of the multiple protruding cutter blades 16a is preferably about 41 to 50 mm.

[0028] As a result, in this embodiment, the round knife 16 rotates with the shrink film 20 being fed in between the rotating roller 17 on which the shrink film 20 is wound, and a plurality of protruding cutter blades 16a sequentially and intermittently form perforations 52 by a group of unit perforations 52a in a row, arranged in a virtual straight line in the feeding direction of the shrink film 20, with a length L of 0.5 to 1.5 mm and spacing S of 1.0 to 7.0 mm, at predetermined pitches between the perforations 52. More specifically in this embodiment, for example, perforations 52 by a group of unit perforations 52a in a row, arranged in a row, are formed at 21 locations with a length of 1 mm and spacing of 1 mm, preferably at a predetermined pitch corresponding to the length of the booklet 50' in the feeding direction.

[0029] In this embodiment, the perforation forming device 15 is provided with an encoder unit 24 supported at the lower end of the slide support portion 15b. The encoder unit 24 is positioned to contact the guide roller 12b adjacent to the downstream side of the rotating roller 17 in the feeding direction, with the feed-out shrink film 20 sandwiched between them, so as to detect the movement speed of the feed-out shrink film 20 and to feed back the detected movement speed to the control panel 22. This makes it possible to accurately and intermittently form a group of unit perforations 52a at a predetermined pitch at predetermined positions on the shrink film 20 supplied toward the article storage section 13.

[0030] The shrink film 20, on which perforations 52 formed by a group of unit perforations 52a at a predetermined pitch with precision and intermittence by the perforation forming device 15, is guided by a plurality of guide rollers 12b of the film supply unit 12, as described above, and after pinholes are further formed at appropriate positions by a pinhole forming device (not shown), it is supplied to the article storage unit 13. The shrink film 20 with perforations 52 that has been supplied to the article storage unit 13 is controlled by operation on the control panel 22, and the intermittently formed perforations 52 are precisely positioned at predetermined positions, for example, on the top surface of each booklet 50', which is a hexahedral-shaped article, supplied sequentially from the article supply unit 11, and as described above, the shrink film 20 is folded back by the holster unit 13a to sequentially wrap the fed-out hexahedral-shaped booklets 50'. The shrink film 20 encasing the booklet 50' is formed into a cylindrical shape containing the booklet 50' by the side sealer portion 13b on the downstream side in the supply direction, as described above. Then, the ends on both the front and rear sides in the supply direction that sandwich the booklet 50' are sealed and cut by the lateral sealer portion 13c, thereby forming the article storage bag 51 before heat shrinking. The formed article storage bag 51 is then sent via the discharge conveyor 19c to the heating section 14 for heat shrinking the shrink film 20, as described above.

[0031] In this embodiment, the heating section 14 for heat-shrinking the shrink film 20 covering the booklet 50' in the formed article storage bag 51 is configured, as shown in Figure 1, to include a first heating tunnel 25 located on the upstream side in the delivery direction and a second heating tunnel 26 located on the downstream side in the delivery direction. As also shown in Figure 5, the first heating tunnel 25 is equipped with an upper pressing belt 25b that moves up and down relative to the conveyor belt 25a, moving the article storage bag 51 being conveyed between it and the conveyor belt 25a while covering and sandwiching its upper and lower surfaces.

[0032] In other words, in this embodiment, the first heating tunnel 25 is configured to include a lower conveyor device 25d that endlessly rotates a conveyor belt 25a using a conveyor motor 25c, and a pressing belt device 25f that endlessly rotates an upper pressing belt 25b using an upper pressing belt motor 25e. The pressing belt device 25f includes a belt support frame 25h having a rectangular frame shape on which a plurality of guide rollers 25g that guide the rotational movement of the upper pressing belt 25b are arranged, and a frame lifting device 25i that is integrally attached to the belt support frame 25h and slides the belt support frame 25h up and down along a support member (not shown) erected adjacent to the lower conveyor device 25d. The raising and lowering of the frame lifting device 25i causes the upper pressing belt 25b, which is supported by the belt support frame 25h and can rotate endlessly, to move up and down relative to the conveyor belt 25a of the lower conveyor device 25d, thereby allowing the item storage bag 51 being transported between the conveyor belt 25a to be moved while being covered and sandwiched between the upper and lower surfaces. In addition to the lower conveyor device 25d and the pressing belt device 25f, the first heating tunnel 25 is also equipped with a heater 25j for heating the inside of the tunnel and a fan motor 25k for circulating hot air.

[0033] These features allow the first heating tunnel 25 to pre-heat and shrink the shrink film 20 covering the outer periphery of the booklet 50', which is the article in the article storage bag 51, before sending the article storage bag 51 to the second heating tunnel 26.

[0034] On the other hand, the second heating tunnel 26 is configured to move the article storage bag 51 while heating it with a conveyor belt 26a, with the top surface of the article storage bag 51 open. Similar to conventional heating tunnels, it is equipped with a conveyor device 26d having a conveyor belt 26a and a conveyor motor 26c for transporting the article storage bag 51, as well as a heater 26j for heating the inside of the tunnel, a fan motor 26k for circulating hot air, and the like.

[0035] In this embodiment of the shrink wrapping apparatus 10, the shrink film 20 covering the outer surface of the booklet 50', which is the article in the article storage bag 51, is heated and shrunk first in the first heating tunnel 25. Then, in the second heating tunnel 26, the remaining portion of the shrink film 20 covering the booklet 50' is heated and shrunk to shrink the booklet 50', thereby forming a shrink-film-wrapped article 50. This makes it possible to easily shrink-wrap a booklet 50', which is the article to be shrink-wrapped, while maintaining its hexahedral shape, even if the booklet 50' has a flexible soft cover, such as a comic book or a paperback.

[0036] In other words, if the booklet 50' being shrink-wrapped is, for example, a comic book or a paperback with a flexible soft cover, then with a conventional heating tunnel, the printed edges of the booklet 50' on the side opposite the binding edge are open. As a result, the compressive force from the contraction of the storage bag makes it easy for the cross-sectional shape perpendicular to the binding edge to curve and warp into an arc shape. Therefore, it becomes difficult to shrink-wrap the booklet while maintaining its hexahedral shape.

[0037] In contrast, in this embodiment, the shrink film 20 covering the outer periphery of the booklet 50' is first heated and shrunk in the first heating tunnel 25, and then the remaining portion is heated and shrunk in the second heating tunnel 26. This makes it possible to pre-determine the shape of the outer periphery of the booklet 50', where the edges of the printed paper are open, by pressing it down with the pre-heated and shrunk shrink film 20 while sandwiching the upper and lower surfaces, thereby effectively preventing the cross-sectional shape perpendicular to the binding margin from becoming curved and warped due to the compressive force caused by the shrinkage of the storage bag when the entire shrink film 20 is heated and shrunk. Furthermore, this makes it possible to easily shrink-package a booklet 50', formed by laminating multiple printed sheets to a predetermined thickness, while maintaining its hexahedral shape.

[0038] In this embodiment, a hexahedral shrink-packaged article 50, which is formed by a shrink-packaging device 10 having the above-described configuration, for example, by covering a booklet 50' with shrink film 20, is provided with a film break-off line 54 formed by perforations 52, which are formed by the perforation forming device 15 described above, as shown in Figures 4(a) and (b), along a virtual straight line 53 that crosses the rectangular surface of the shrink film 20 on that surface of the hexahedral shape. The film break-resistant line 54 is formed by having unit perforations 52a of the perforations 52 constituting the film break-resistant line 54 arranged in 5 to 22 locations with a length L of about 0.5 to 1.5 mm and an interval S of about 1.0 to 7.0 mm, more preferably arranged in 6 to 15 locations with a length of, for example, 0.5 to 1.0 mm and an interval of 3.0 to 6.5 mm, and is formed only in a length region M of about 30% of one of the shorter sides. In this embodiment, the length region M has a total length of, for example, about 42.5 mm, and the central part is located 50 mm from the lower shorter side.

[0039] Furthermore, in the shrink-wrapped article 50 of this embodiment, a pair of markings 55 indicating the direction of separation are preferably drawn on both sides of the film break line 54 on one rectangular surface of the shrink film 20 where the film break line 54 formed by the perforations 52 is located.

[0040] In this embodiment, the article 50' having a hexahedral shape, which is covered with shrink film 20 to become a shrink-packaged article 50, is, as described above, a booklet 50' formed by laminating a plurality of printed sheets, preferably having a rectangular planar shape, to a predetermined thickness. The booklet 50' is, for example, a comic book or a paperback, with a soft cover. The shrink-packaged article 50, which is made by packaging the soft-cover booklet 50', is formed to have a flattened hexahedral shape with a rectangular planar shape having a vertical width of approximately 120 to 200 mm and a horizontal width of approximately 100 to 130 mm, and a thickness of approximately 5.5 to 50 mm. By passing through the heating section 14 by the first heating tunnel 25 and the second heating tunnel 26 described above, it is not curved or warped into an arc shape, but maintains its hexahedral shape firmly, and is neatly shrink-packaged in a desirable appearance.

[0041] Furthermore, in this embodiment, the shrink film 20 on one rectangular surface (preferably the top surface) of the hexahedral shrink-wrapped article 50 is provided with a film break line 54 formed by perforations 52 along a virtual straight line 53 that crosses that surface. From the viewpoint of making it easier to place the fingers of both hands on either side of the perforations 52 when removing the booklet 50', which is the article, from the shrink-wrapped article 50, it is preferable that the film break line 54 formed by perforations 54 is formed only on a portion of the virtual straight line 53 that extends parallel to the long side direction of the rectangular surface, and more preferably on a portion of the virtual straight line 53 that crosses the center of the width (horizontal width) in the short side direction of the rectangular surface.

[0042] Furthermore, in this embodiment, the film breakage line 54 is formed by having unit perforations 52a of the perforations 52 constituting the film breakage line 54, preferably with a length L of about 0.5 to 1.0 mm and spaced apart at intervals S of about 3.0 to 6.5 mm in 6 to 15 locations, and preferably as part of a virtual straight line 53 parallel to the long side direction that crosses the center in the width direction, for example, only in a region M of preferably about 30% of the length on one short side of one rectangular surface. As a result, when the article storage bag 51 before the shrink film 20 is heated and shrunk passes through the heating section 14, particularly the second heating tunnel 26, even if the air inside the heated bag expands, the unit perforations 52a constituting the perforations 52 are arranged in a manner of appropriate length L and spaced apart at appropriate intervals S, and are formed only in a part of the virtual straight line 53, so it is possible to effectively avoid rupture due to internal pressure caused by the expansion of air. Furthermore, as a result, when removing the shrink film 20 from the shrink-wrapped hexahedral shrink-wrapped article 50 to take out the booklet 50', the unit perforations 52a that make up the perforations 52 are formed along a virtual straight line 53 with an appropriate length L and an appropriate interval S, so the film break line 54 is not difficult to find or break, and it can be broken with a simple operation, for example, by placing the fingers of both hands on either side of the perforations 52 and pulling them apart. Moreover, the remaining part can be easily broken using the film break line 54 formed by 52 as a starting point, and the shrink film 20 can be removed, making it possible to easily and smoothly take out the booklet 50'.

[0043] Therefore, with the shrink-wrapped article 50 formed by the shrink-wrap device 10 of this embodiment, perforations 52, which serve as film break-off lines 54, are provided on one of the hexahedral surfaces of the shrink film 20 covering the booklet 50', which is a hexahedral article. These perforations 52 are provided in a manner that prevents breakage during heating, but allows for easy breakage when removing the article 50'. This ensures that a stable packaging form is maintained during distribution and sales, and that the article 50' can be easily removed during use.

[0044] Furthermore, according to the shrink packaging apparatus 10 of this embodiment, it becomes possible to easily form perforations 52, which serve as film break-off lines 54, on any of the hexahedral surfaces of the shrink film packaging article 50 covered by the shrink film 20, in a manner that prevents breakage during heating, while also making it easy to break when removing the booklet 50', which is the article.

[0045] Furthermore, in this embodiment, the shrink packaging apparatus 10 is provided with a known printing device (not shown) controlled by the operation of the control panel 22, downstream of the second heating tunnel 26 of the heating section 14. As described above, this printing device can draw a pair of markings 55 (see Figures 4(a) and (b)) on both sides of the film breakage line 54 of the shrink film 20 on one side of the shrink packaged article 50, preferably consisting of arrows, to indicate the direction in which the film breakage line 54 can be pulled away or separated. The markings 55 indicating the direction in which the film breakage line 54 can be pulled away or separated can be arrows or other various other marks that indicate different separation directions.

[0046] It should be noted that the present invention is not limited to the embodiments described above and can be modified in various ways. For example, the article to be shrink-wrapped by the shrink-wrapping device of the present invention does not necessarily have to be a booklet 50', but may be any other article having a hexahedral shape, such as a hexahedral package containing software media, CDs, or DVDs. [Explanation of Symbols]

[0047] 10 Shrink packaging device 11 Goods Supply Department 11a Booklet hopper section 11b Clamping and conveying section 11c Extrusion Piston 11d Upper retaining belt 11e Lower pressure belt 12 Film supply unit 12a Film holder 12b Guide roller 12c Film Sprinkler 13. Storage Section for Goods 13a Home Club 13b Side seal section 13c Yokoshira section 14 Heating section 15 Perforation forming device 16 Round Knife 16a Protruding cutter blade 17 Rotating Rollers 18. Retraction mechanism (slide mechanism) 19. Means of transportation 19a Supply conveyor 19b Feed conveyor 19c discharge conveyor 20 Shrink film 21 Defective product automatic exclusion device 22 Control panel 23. Scrap winding machine 24 encoder units 25. First heated tunnel 26. Second heated tunnel 50 Shrink film packaged items 50' booklet 51. Item storage bag 52 perforations 52a Unit perforation 53. A virtual straight line 54. Film prone to breakage. 55 Marking

Claims

1. A shrink packaging apparatus comprising: an article supply unit for supplying articles having a hexahedral shape; a film supply unit for supplying heat-shrinkable shrink film; an article storage unit for storing the articles in a storage unit made of shrink film to form an article storage bag before heat shrinking; and a heating unit for shrink-packaging the stored articles by heating the formed article storage bag to heat-shrink the shrink film, wherein The film supply unit is equipped with a perforation forming device for forming perforations along the supply direction of the shrink film, thereby providing an easy-tear line on one side of the hexahedral shrink-packaged article after shrink packaging. The perforation forming device includes a disc-shaped round knife equipped with a plurality of protruding cutter blades arranged at intervals in the circumferential direction, wherein the plurality of protruding cutter blades are arranged in a continuous manner only in a portion of the circumferential direction on a hypothetical straight line traversing one surface of the shrink-wrapped article, and the plurality of unit perforations constituting the perforation are formed in a continuous manner at intervals of 1.0 to 7.0 mm, with a length of 0.5 to 1.5 mm, at 5 to 22 locations. The round knife of the perforation forming apparatus is configured to form the perforations with a plurality of protruding cutter blades while rotating, with the shrink film sandwiched between it and a rotating roller around which the shrink film is wound. The perforation forming apparatus is a shrink packaging apparatus that includes a reciprocating mechanism for moving the round knife forward and backward relative to the rotating roller.

2. The shrink packaging apparatus according to claim 1, wherein the plurality of protruding cutter blades are provided connected only to a portion of the circumferential direction so that the plurality of unit perforations constituting the perforations are formed by connecting 6 to 15 locations with a length of 0.5 to 1.0 mm and at intervals of 3.0 to 6.5 mm.

3. The shrink packaging apparatus according to claim 1 or 2, wherein the article having the hexahedral shape is a booklet formed by laminating a plurality of printed sheets having a rectangular planar shape to a predetermined thickness.

Images