| 摘要 |
The invention provides rolls, belts and other biasable members having at least one layer or coating of an elastomeric resilient crosslinked polyurethane formed by reacting (a) a polyisocyanate prepolymer comprising the reaction product of a saturated aliphatic polyisocyanate, a saturated cycloaliphatic polyisocyanate, or an aromatic polyisocyanate and a polyol free of aliphatic unsaturation, preferably a polyalkylene glyocl in which the alkylene group contains 2 to 8 carbon atoms, and (b) a hardening mixture comprising a polyol of (a) or a diamine free of aliphatic unsaturation, or a mixture thereof and, as a conductivity control agent, from 0.001 to 5.0 weight percent, based on the total weight of (b), of a complex of ethylene glyocl or an oligoethylene glyocl selected from the group consisting of di-, tri- and tetraethylene glyocl with an ionizable zinc halide salt consisting of zinc chloride in the presence of an organometallic catalyst in which bismuth constitutes the metallic component thereof. The resistivity of the elastomeric resilient polyurethane coating on the biasable member is controlled or adjusted to within a desired level of resistivity due to the inclusion of the conductivity control agent in the crosslinked polyurethane elastomer. The utility of such biasable members is in the transfer of toner images from an electrostatographic element comprising a conductive support surface to a final support sheet where the member electrically cooperates with the conductive support surface to establish a directional force field therebetween.
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