| 摘要 |
PURPOSE:To prevent a type proper from being typed to more than a certain depth by a method wherein a curvature radius for chamfering a very small portion of the surface is made equal to the curvature radius at the corner of the printing surface and a curvature radius for chamfering the portion toward the rear surface side is gradually made greater. CONSTITUTION:In the punched tilted portion from the corner of a type surface 2 to the corner of its rear surface, a curvature radius (r) for chamfering a very small surface corner 4 proceeding from the type surface 2 to the rear surface side is made roughly equal to the curvature radius r1 of the corner of the type surface 2. Moreover, the curvature radius R for chamfering the lower corner 5 on the rear surface side is made greater than the surface corner 4 toward the rear surface side. The type proper 1 is prevented from being typed to a certain depth at the lower corner 5 and the curvature radius (r) for chamfering even in the surface corner 4 is made roughly constant. Accordingly, even if the type surface 2 wears within this range, the printing type will not loose its sharpness. |
