| 摘要 |
PURPOSE:To restrict noises and vibrations generated at a printing time, improve the printing efficiency and obtain superior durability of types, by lowering the restitution of a platen roller and making the ratio of the diameter of a solid columnar base member to 45-75% to the outer diameter of the platen roller. CONSTITUTION:An elastic layer 3 is provided in an outer periphery of a solid columnar base member 1 which has rotary shafts 2 at both end faces thereof, thereby to form a platen roller. The ratio of the outer diameter l of the base member 1 is set to 45-75% to the outer diameter L of the platen. The hardness of the elastic layer 3 is 95+ or -3 JISA at 20-25 deg.C on the basis of JISK 6301. Moreover, the restitution of the elastic layer 3 is 4-7% at 20-30 deg.C based on the JISK 6301. Accordingly, rebounding of a hammer at the printing time is restricted, while improving the efficiency of the hammering energy. Thus, the printing efficiency can be favorably improved, and at the same time, the impact load can be reduced, thereby enhancing the durability of printing elements such as a daisy wheel, etc. |
