PURPOSE: To lengthen the life of an ink ribbon as well as to permit high-quality printing by a method in which the printing face other than the end portion of the type projection is covered with a resin film, and only the end portion of the printing face is selectively rounded.

CONSTITUTION: The surface of the type projection 13 is all covered with an ultraviolet rays-sensitive resin 14, the resin film 14 is exposed to irradiation of ultraviolet rays from a light source 16 through a mask 15 to harden only the resin film 17 on the necessary printing face 12, resulting in the exposure of acute end portion C of the printing face. In the type belt whose printing face 12 is protected by the resin film 17, the acute corners of the end portion C of the typing face is rounded by an etching treatment but no damage occurs on the important printing face 12. The acute end portion C can thus be easily rounded in a desired size by specifying the dimensions of the light-transmissive portion of the mask 15 used for light exposure. After the etching treatment, the resin film 17 on the type projection 13 is removed out by a releasing liquid, etc.