| 摘要 |
PURPOSE:To round the tip of a wire pin off by grinding, by a method wherein when the wire pin of a printing head is aged by driving the wire pin a fixed number of times to stabilize its operation after assembly of the printing head, the wire pin is struck against the elastic platen containing abrasive grain. CONSTITUTION:24 wire pins 11 integrated into a printing head 1 are worked firstly by grinding in order to uniform the length of the pin tip extruded from a head body. Because wear powder attached to the hole or the like of a wire pin guide due to this working, again process is carried out after this operation in order to remove grinding chips and to achieve the stabilization of the sliding property between the guide hole and the outer periphery of the wire pin. In an aging process the wire pin 11 is driven about sixty million times to strike the platen for rounding off 21. Thereby, the tip of the wire pin 11 is ground with abrasive grains contained in the platen to form a suitable roundness of 7-10mum. By the wire pin having such a tip roundness the marring of an ink ribbon in actual printing operation is lightened and consequently, the life of said ribbon is extended. |
