| 摘要 |
PROBLEM TO BE SOLVED: To enhance easy unsealing and reliability of an envelope which is opened by tearing its edge part along a perforation. SOLUTION: An unsealing part of an envelope is composed of a surface sheet 2, an upper folding piece sheet 7, and a back sheet 3. The upper folding piece sheet 7 is stuck to the back sheet 3. Only one of perforations 14 and 15 is cut in the surface sheet 2 and the back sheet 3, respectively, and three perforations 16a-16c extending in parallel to each other are cut in the upper folding piece sheet 7. Since the perforation 15 of the back sheet 3 is surely superposed on a perforation area 19 of the upper folding piece sheet 7, the back sheet 3 and the upper folding piece sheet 7 are reliably and correctly torn from each other. COPYRIGHT: (C)2009,JPO&INPIT
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