| 摘要 |
PURPOSE:To obtain a platen roller free of possibility of defective printing due to residual depression, by fitting to the periphery of a core member a rubber member such that the degree of relaxation of stress after a predetermined period of time under a load is decreased, constant or slightly increased with a rise in temperature in a normal temperature region. CONSTITUTION:The degree of relaxation of stress after a predetermined period of time under a load is the value of P0-P, where P is the stress measured after the predetermined period of time under the condition where a fixed load P0 is exerted on a material to be tested by a load cell for a compression test or the like and the material is left to stand while maintaining the strain. A rubber member 2 can be obtained by blending a raw material polymer, carbon, an inorganic filler, an oil, sulfur, a vulcanizing assistant, a vulcanization accelerator, stearic acid and a peroxide as a cross-linking agent, a plasticizer, a reinforcing agent or the like. The raw material polymer may be a rubber such as SBR, NBR and BR, a thermoplastic elastomer such as RB and SBS, or a blend thereof. The inorganic filler may be calcium carbonate, clay or the like. The vulcanization accelerator may be an aldehydeamine, guanidine or the like or a combination thereof. |
