| 摘要 |
PURPOSE: To obtain a sheet film unit which is mass-produced at low cost by constituting a sheath of edge parts where a rectangular plate part and a U-shaped groove are formed and integrally molding it of resin by injection molding. CONSTITUTION: The sheet film unit 1 is constituted of a sheet film 2 of 4×5 inch size and the sheath 3 housing the sheet film 2. The sheath 3 is integrally injected and molded of resin such as polyethylene. Therefore, the unit 1 is mass-produced at low cost. The sheath 3 is constituted of the plate part 3a to support and cover both sides of the base of the film 2 and edge parts 3b to 3d where the groove to hold the edges of three sides 2b to 2d except the short side 2a of the film 2 is formed. By providing plural gates 10 to 14 on one side 3c side in parallel, the cross sectional area of the gates 11 to 13 in the center part is made larger than that of the gates 10 and 14 on both sides. Thus, the excellent sheath 3 is stably injected and molded without causing burr and warpage.
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