Tokai Rubber Industries, Ltd.

Yoshihiro Wago

Satoshi Suzuki

Hitoshi Yoshikawa

Keita Shiraki

Yuma Yoshida

Hideki Sendo

Yasuhiro Iwamoto

A urethane composition for making a sheet transport roll, the composition comprising: (A) a polyether polyol blend containing polytetramethyleneether glycol (PTMG) and polypropylene glycol (PPG) in a weight ratio of PTMG/PPG&equals;99/1 to 50/50; (B) a polyisocyanate; and (C) a chain lengthening agent; the urethane composition in a cured state having a hardness of not smaller than 40, and a crosslinking density of 0.15 to 0.8 mmol/cm or an allophanate bond concentration of 0.03 to 0.07 mmol/g.

Urethane composition for sheet transport roll, and sheet transport roll produced by employing the urethane composition

A retard roller of non-ground surface type which is virtually free from adhesion of paper dust thereby to have an excellent friction coefficient sustain ability, and which is free from creaky noises at a relatively low sheet feeding speed; a retard roller of non-ground surface type having little variation in outer diameter; and a sheet feeder employing such a retard roller. The retard roller comprises a roller body and a shaft extending axially therethrough, the roller body having a textured roller surface comprising a multiplicity of island portions ( ) and a sea portion ( ) recessed from the island portions, the island portions and the sea portion each having a multiplicity of fine projections ( ). The ratio S /S of the total area S of the island portions to the area S of the sea portion preferably is 0.25 to 0.55. The fine projections preferably each have a height of 3 to 25 &mgr;m.

Retard roller and sheet feeder

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Gifu-ken, Japan

Yoshihiro Wago