Package making – Methods – Closing package or filled receptacle
Reexamination Certificate
2001-01-11
2003-12-23
Rada, Rinaldi I. (Department: 3721)
Package making
Methods
Closing package or filled receptacle
C053S392000, C053S329300, C053S329500, C053S386100, C053S488000
Reexamination Certificate
active
06666005
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a packaging method and packaging apparatus. More particularly, the present invention relates to a packaging method and packaging apparatus wherein a tray, having a flange and an opening surrounded by said flange on its upper face and containing an article to be packaged, is covered with a film over the opening and the film is welded to the flange.
BACKGROUND ART
Conventionally fresh fish and meat, as well as side dishes and other processed foods, have been packaged using the “overlap method.” The overlap method involves putting the food product into a tray and wrapping the entire tray with a film.
Consequently, the planar size of the film must be several times larger than the planar size of the tray because both the tray and the entire food product must be covered and the ends of the film must overlap in order to form a seal. Furthermore, such packages are often sealed by pressing a hot plate against the overlapped ends of the film on the bottom of the tray, which results in an inferior seal.
Meanwhile, there are some cases where another method (hereinafter called the “top-seal method”) is used instead of the overlap method. With the top-seal method, the film is placed only over the opening provided in the upper face of the tray and the film is thermally welded to the tray along the periphery of the hole. Using the top-seal method can reduce film consumption by half in comparison with the overlap method.
The top-seal method has been used chiefly for packaging shimeji and other varieties of mushroom. One common form of the top-seal method is to apply an adhesive to the sides of the tray around the opening and bond the ends of the film to the tray when the film is placed over the opening. Another common form is to sandwich the tray and a piece of film that is larger than the planar size of the tray between two tools and apply pressure and heat to thermally weld the film to the tray.
The disadvantage with both of these top-seal methods is that they require tooling matched to the size and shape of the tray. Consequently, industries that need to use multiple tray types to package a variety of different articles often use the overlap method instead of the top-seal method. Although the top-seal method provides such merits as reduced film consumption and improved sealing characteristics, it is often impractical because a separate set of tools must be prepared for each different size and shape of tray.
DISCLOSURE OF INVENTION
The object of the present invention is to provide a packaging method and corresponding packaging apparatus that allow an article placed on a tray to be sealed with a film using the top-seal method but do not require the preparation of tooling for each different size and shape of tray.
A packaging method in accordance with the first aspect of the invention is provided with first, second, third, and fourth steps. In the first step, the article to be packaged is put on a tray having an opening in its upper face; in the second step, the opening in the tray is covered with a film; in the third step, a heated hot member is touched, in a direction intersecting with a vertical direction, against the film on a portion of the tray near the opening where the film touches; and in the fourth step, at least one of the hot member or the tray is moved.
More specifically, in the first step of the packaging method described in the first aspect, a food product or other article is placed on a tray. In the second step, the opening in the upper face of the tray is covered with a film so that the film is touching a portion of the periphery of the tray opening. In the third step, the film on a portion of the tray near the opening where the film touches is pressed with a heated hot member in a direction intersecting with a vertical direction. In other words, the hot member is applied at an angle to a portion of the tray near the opening. In the fourth step, at least one of the hot member or the tray is moved while the hot member being applied at an angle to a portion of the tray near the opening. As a result, the entire portion of the film that is touching the tray in the area surrounding the opening is thermally welded to the tray.
With this method, since at least one of the hot member or the tray is moved, the hot member and the periphery of the tray opening are moved relative to each other. Consequently, various shapes and sizes of tray can be accommodated so long as the size of the tray is within certain limits. Unlike conventional top-seal methods, it is not necessary to prepare tools for each different type of tray or to spend time changing those tools each time a different tray is used. Therefore, equipment costs can be reduced and the efficiency of packaging operations can be improved.
Also, since the hot member is applied to a portion of the tray near the opening from a direction that intersects with a vertical direction, the hot member only comes in contact with a portion of the tray near the opening and does not come in contact with the portion of the film covering the tray opening. Consequently, the portion of the film that covers the opening is less likely to melt or develop tiny holes.
It is preferred that a pressure applying mechanism and controller be provided so that the pressure at which the hot member is applied to a portion of the tray near the opening and the speed at which the hot member and the periphery of the tray opening are moved relative to each other can be set to levels that are well matched to the materials from which the tray and film are made. It is also preferred that a controller and an angle adjustment mechanism be provided so that the degree to which the heating means heats the hot member and the angle at which the hot member is touched against the portion of the tray near the opening can be adjusted as necessary and appropriate.
A packaging method in accordance with the second aspect of the invention is a method as recited in the first aspect, wherein, either one or two or more hot members are touched against the film on a portion of the tray near the opening in the third step and either one or two or more hot members move along the periphery of the opening in the tray in the fourth step.
By touching two or more hot members against a portion of the tray near the opening, the amount by which each hot member must be moved along the periphery of the tray opening can be reduced in comparison with amount of movement required when only one hot member is used. That is, when only one hot member is used, the hot member must be moved at least one full revolution around the tray opening in order to weld the film to the entire periphery of the tray opening. But, when two or more hot members are used, the film can be welded to the entire periphery of the tray opening without moving each hot member a full revolution around the tray opening. Thus, the time required to move in the fourth step can be reduced and the efficiency of the packaging process can be improved.
Conversely, costs can be reduced when only one hot member is applied to a portion of the tray near the opening because, although the hot member must be moved at least one full revolution around the tray opening in order to weld the film to the entire periphery of the tray opening, fewer hot members need to be prepared.
A packaging method in accordance with the third aspect of the invention is a method as recited in the first or second aspect, wherein, during the third and fourth steps, the hot member not only thermally welds the film to a portion of the tray near the opening but also cuts the outer portion of the thermally welded film.
This method improves the efficiency of the packaging process because the film is welded and cut simultaneously.
It is also feasible to thermally cut the outer portion of the thermally welded film by using the hot member that welds the film to the tray. The hot member can thermally cut the film more reliably if a tensile force is applied to the film.
A packaging method in accordance with the fourth aspect of the invention is
Kawanishi Norio
Oguri Toshio
Ohshita Minoru
Ishida Co. Ltd.
Rada Rinaldi I.
Shinjyu Global IP Counselors, LLP
Truong Thanh
LandOfFree
Packaging method and packaging apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Packaging method and packaging apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Packaging method and packaging apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3179402