Producing method of film with through-holes

#This invention relates to a producing method of a film with through-holes.

#Generally, such film is made of a plastic film. A punching machine is used to form through-holes on the film. The punching machine is arranged to pierce the film with needles. In order to improve the accuracy of dimensions (such as diameters and pitches) of the through-holes, it is necessary to improve an operation accuracy of a punching machine. However, such improvement of the punching machine may increase the producing cost of the film.

#Accordingly, there is a strong demand for a producing method of a film with through-holes which achieves a high accuracy of the dimensions of the through-holes, without increasing the producing cost of the film.

#FIGS. 1A, 1B, 1C and 1D are schematic views showing a producing method of a film with through-holes according to a first embodiment;

#FIG. 2 is a perspective view of the film of FIG. 1;

#FIG. 3 is a sectional view of a ink transfer printer using the film of FIG. 2;

#The embodiments of the producing method of a film with through-holes according to the present invention are described below.

#FIGS. 1A, 1B, 1C and 1D are schematic views showing a producing method of a film with through-holes according to a first embodiment. A film 2 shown in FIG. 1A is made of polytetrafluoroethylene (Teflon (trademark)). The film 2 has a square shape, each side thereof having the length L. The thickness t of the film 2 is from 0.03 to 0.08 mm. In FIG. 1A, X-direction and Y-direction are defined along two adjacent sides of the film 2.

#As shown in FIG. 1B, the film 2 is stretched in two directions. A clamp mechanism is used to stretch the film 2. The clamp mechanism has four clamps 110 which respectively hold four sides of the film 2 (one of clamps 110 is not shown in FIG. 1B) and stretches the film 2 in X-direction and Y-direction. The film 2 is stretched so that the length of each side becomes 2L, and so that the thickness of the film 2 becomes t/4.