| 摘要 |
The element carries type faces capable of being deflected into printing contat with an impression paper, the element being formed of an elastic material having a modulus of at least 8,000 psi. at 100 cycles/sec. and a dynamic coefficient of friction against the impression paper of at least 1 at 600 feet/min. The element, which may be in the form of a wheel, disc, basket or endless tape, is suitable for use in high-speed printers in printing telegraph systems (e.g. the printer in GB. 1, 169, 239). The elastic material of the element is pref. a polyether polyurethane having a Shore A hardness of 90. Other suitable elastic material are polyester and polyamide polyurethanes, epoxy-polyurethane blends, chlorosulphonated polyethylene and polyacrylic rubber. |
