Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2000-11-16
2003-10-14
Aftergut, Jeff H. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S184000, C156S191000, C156S245000
Reexamination Certificate
active
06632312
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for manufacturing annular, tubular, cylindrical, and belt-like films used as a conveyor belt for conveying precision parts to a predetermined position with high positional accuracy, and a closed package for packaging or containing goods.
The present invention is principally used as functional parts of an image forming apparatus.
BACKGROUND OF THE INVENTION
A conventional tubular film manufacturing method and apparatus for forming a sheet film into a tubular film use a heating furnace as a film heating means as proposed in Japanese Patent Laid-Open No. 8-187773.
In this prior art, however, a cylindrical member on which a sheet film is wound and a tubular mold member are placed in a heating furnace held at a certain predetermined temperature. Therefore, the heat is conducted from the tubular mold member as an outer member, so it takes a long time for the film and the cylindrical member to reach the temperature necessary for molding.
Also, since the heat is conducted from the tubular mold member as an outer member, this tubular mold member expands first by the heat to increase the gap with respect to the film wound on the cylindrical member. This makes the conduction of heat to the film and the cylindrical member more and more difficult. Consequently, it takes a long time to reach the necessary molding temperature.
Additionally, in the technique disclosed in Japanese Patent Laid-Open No. 8-187773, the tubular mold member and the cylindrical member used in heat-molding have straight shapes.
FIG. 19
shows the shapes of the conventional tubular mold member and cylindrical member. A sheet film
1006
is wound on a cylindrical member
1002
having a constant outside diameter. This sheet film
1006
wound on the cylindrical member
1002
is inserted into a tubular mold member
1004
and molded by heating. After that, the film formed into the shape of a tube is peeled from the tubular mold member
1004
and cut into a predetermined size to complete a tubular film.
In this prior art, however, the workability of the operation of winding the sheet film on the cylindrical member is low, and this operation cannot be easily automated.
Also, when the tubular film is peeled from the tubular mold member after the heat-molding step, the workability is very low because the tubular film is sticking to the inner surface of the tubular mold member and there is no portion to start peeling. This operation is also difficult to automate.
Ribs can be formed on the inner circumferential surface at the two end portions of the tubular film to prevent meandering of the film when the film is incorporated into a product. When this is the case, ribs must be adhered in a post-process.
Conventionally, to cut a tubular film an operator cuts the two ends of the film by using a cutter or the like.
Also, a method disclosed in Japanese Patent Laid-Open No. 5-307291 is known as a method of extending wrinkles of a film.
In these prior art references, however, it is difficult to cut the end portions of a tubular film perpendicularly to the edge line of the film. Also, a tubular film is creased when cut. Furthermore, since wrinkles produced on a tubular film when the film is cut cannot be removed, the end portions of the film cannot be linearly cut.
No effective means has been proposed which extends wrinkles of a tubular film with high workability or without complicating the apparatus.
Conventionally, when a tubular film is manufactured by winding a sheet film on a cylindrical member, as shown in
FIG. 36
, the end portion of a sheet film
1006
is temporarily fastened by adhesive tapes
1008
or the like so as to prevent displacement from the outer circumferential surface of a cylindrical member
1002
. If the end portion of the sheet film is not fixed to the cylindrical member, the sheet film is loosely wound to produce winding displacement or wrinkles. Consequently, no tubular film having a desired thickness can be obtained after molding.
Also, as disclosed in Japanese Patent Laid-Open No. 10-16093, a suction portion can be formed over the entire width on the outer circumferential surface of a cylindrical member on which a sheet film is wound.
In the former prior art, however, when the adhesive tapes are peeled after the sheet film is wound on the cylindrical member, the sheet film sometimes breaks, and the operation of peeling is troublesome. This makes the operation difficult to automate.
The method disclosed in Japanese Patent Laid-Open No. 10-16093 has the following problem. The sheet film wound on the cylindrical member is inserted into a tubular mold member in the subsequent step and molded into a tubular film by heating. However, since suction holes are formed over the entire width in the outer circumferential surface of the cylindrical member, portions of the film on these suction holes enter the holes during heat-molding. This forms projections as functional defects in the product.
SUMMARY OF THE INVENTION
The present invention, therefore, has been made in consideration of the above situation, and has as its object to provide a manufacturing method and apparatus capable of obtaining a high-accuracy tubular film at low cost by performing molding within a short time period.
It is another object of the present invention to provide a manufacturing method and apparatus capable of obtaining a high-accuracy tubular film at low cost by automatization.
It is still another object of the present invention to provide a cutting apparatus having good workability and capable of accurately cutting end portions of a tubular film at low cost.
It is still another object of the present invention to provide a manufacturing method and apparatus capable of obtaining a high-accuracy tubular film at low cost by automatizing winding of a sheet film.
To solve the above conventional problems and achieve the objects, a tubular film manufacturing method according to the present invention is a tubular film manufacturing method of winding a thermoplastic sheet film on a cylindrical member, fitting a tubular mold member on the outside of the wound film, and heating the film together with the cylindrical member and the tubular mold member, thereby molding the sheet film into a tubular film, characterized in that heating means is placed in a central portion of the cylindrical member to heat the cylindrical member from the central portion and join winding start and end portions of the film.
A tubular film manufacturing apparatus of the present invention is a tubular film manufacturing apparatus for winding a thermoplastic sheet film on a cylindrical member, fitting a tubular mold member on the outside of the wound film, and heating the film together with the cylindrical member and the tubular mold member, thereby molding the sheet film into a tubular film, characterized in that heating means is placed in a central portion of the cylindrical member to heat the cylindrical member from the central portion and join winding start and end portions of the film.
A tubular film manufacturing method according to the present invention is a tubular film manufacturing method of winding a thermoplastic sheet film on a cylindrical member, fitting a tubular mold member on the outside of the wound film, and heating the film together with the cylindrical member and the tubular mold member, thereby molding the sheet film into a tubular film, characterized in that the outer diameter at two end portions of the cylindrical member is made smaller than the outer diameter at a central portion thereof, and the length in an axial direction of the central large-diameter portion is made shorter than the width of the sheet film.
A tubular film cutting apparatus according to the present invention is a tubular film cutting apparatus for cutting two end portions of a tubular film, characterized by comprising a rotatable support member for supporting an inner-diameter portion of the tubular film, a driving source for rotating the support member, a first roller capable of contacting the support member
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