Method of and apparatus for making heat-sensitive stencil and heat-sensitive stencil material

Abstract

When thermally perforating a thermoplastic resin film of heat-sensitive stencil material by the use of a thermal head, supply of energy to the thermal head is cut at a time the diameter of the perforations becomes not smaller than 65% and not larger than 95% of a target diameter of the perforations.

What is claimed is:  
     
         1 . A thermoplastic resin film for stencil material which is scanned by a heat source, which is heated through a supply of energy, the heat source having a scanning pitch in both a main scanning direction and a sub-scanning direction such that the thermoplastic resin film is thermally formed with perforations arranged in the main scanning and sub-scanning directions wherein 
 the heat shrinkable properties of the thermoplastic resin film are such that the diameter of the perforations is enlarged after cutting the supply of energy to the heat source to from 105% to 154% of that at the time the supply of energy to the heat source is cut.    
     
     
         2 . A thermoplastic resin film for stencil material which is scanned by a heat source, which is heated through a supply of energy, the heat source having a scanning pitch in both a main scanning direction a sub-scanning direction such that the thermoplastic resin film is thermally formed with perforations arranged in the main scanning and sub-scanning directions, wherein 
 the heat shrinkable properties of the thermoplastic resin film are such that the area of the perforations is enlarged after cutting the supply of energy to the heat source to from 110% to 237% of that at the time the supply of energy to the heat source is cut.    
     
     
         3 . A heat-sensitive stencil material which comprises a thermoplastic resin film and a porous support sheet laminated together and is scanned by a heat source, which is heated through a supply of energy, the heat source having a scanning pitch in both a main scanning direction and a sub-scanning direction such that the thermoplastic resin film is thermally formed with perforations arranged in the main scanning and sub-scanning directions, wherein 
 the heat shrinkable properties of the stencil material are such that the diameter of the perforations is enlarged after cutting the supply of energy to the heat source to from 105% to 154% of that at the time the supply of energy to the heat source is cut.    
     
     
         4 . A heat-sensitive stencil material as defined in  claim 3  in which the porous support sheet is of paper made of synthetic fiber blended with natural fiber.  
     
     
         5 . A heat-sensitive stencil material as defined in  claim 3  in which the porous support sheet and the thermoplastic resin film are laminated by adhesive.  
     
     
         6 . A heat-sensitive stencil material which comprises a thermoplastic resin film and a porous support sheet laminated together and is scanned by a heat source, which is heated through a supply of energy, the heat source having a scanning pitch in both a main scanning direction and a sub-scanning direction such that the thermoplastic resin film is thermally formed with perforations arranged in the main scanning and sub-scanning directions, wherein 
 the heat shrinkable properties of the stencil material are such that the area of the perforations is enlarged after cutting the supply of energy to the heat source to from 110% to 237% of that at the time the supply of energy to the heat source is cut.    
     
     
         7 . A heat-sensitive stencil material as defined in  claim 6  in which the porous support sheet is of paper made of synthetic fiber blended with natural fiber.  
     
     
         8 . A heat-sensitive stencil material as defined in  claim 6  in which the porous support sheet and the thermoplastic resin film are laminated by adhesive.