Feed/transport roller
The invention provides a feed/transport roller formed of polyurethane material, which roller has high wear resistance as well as low hardness for providing excellent sheet feeding capacity and which meets a recent requirement; i.e., high durability for allowing high-speed operation. The feed/transport roller has an elastic layer formed of a castable polyurethane produced through reaction of a polyester-polyol having a number average molecular weight of 1,000 to 3,000 with a polyisocyanate, wherein the elastic layer is formed from the polyester-polyol, the polyisocyanate, an adipic acid ester derivative serving as a plasticizer, a short-chain diol having a molecular weight of 70 to 120 serving as a chain-extender, and a triol having a number average molecular weight of 3,000 to 5,000 serving as a cross-liking agent.
1. A feed/transport roller having an elastic layer comprising a castable polyurethane, which is a reaction product of a polyester-polyol having a number average molecular weight of 1,000 to 3,000 with a polyisocyanate, wherein the elastic layer is formed from the polyester-polyol, the polyisocyanate, an adipic acid ester derivative serving as a plasticizer, a short-chain diol having a molecular weight of 70 to 120 serving as a chain-extender, and a triol as a cross -liking agent,
wherein the adipic acid ester derivative has an ether moiety in the molecule and is employed in an amount of 5 to 40 parts by weight with respect to 100 parts by weight of the polyester-polyol, and
wherein the triol has an ether moiety in the molecule and has a number average molecular weight of 3,000 to 5,000 serving as a cross-linking agent.
2. A feed/transport roller according to claim 1 ; wherein the polyester-polyol is a diol produced through condensation of at least one species of nonanediol and methyloctanediol with a dibasic acid.
3. A feed/transport roller according to claim 1 , wherein the elastic layer has a rubber hardness Hs (JIS A type) of 20 to 50°.
4. A feed/transport roller according to any one of claims 1 to 3 , wherein the roller exhibits a ratio of maximum value (Max) of an output waveform to minimum value (Min) of the output waveform (Max/Min) falling within a range of 1.00 to 1.20, the output waveform being obtained during measurement of friction coefficient.