| 摘要 |
<p>An "overstrike" ink-ribbon comprises a sheet support coated with an ink dispensing layer comprising a plastics in which is dispersed a colouring paste based on a mineral oil contg. a colouring pigment, fillers and a wetting agent. The improvements are that the oil contains 25-40% aromatic hydrocarbons in which 30-40% of the satd. C atoms are of the cycloaliphatic type, the wetting agent is an aliphatic amine salt and the filler is a finely divided material with accumulation effect and large internal surface area, the viscosity of the paste being 4,000-10,000 m Pa.s (20 deg.C) For use in a typewriter. The ink-ribbon allows "overstrike" to be increased by a factor of at least 5, even on high speed, printing wheel machine. Sharp and intensely black characters are obtd.</p> |
