Retard roller and sheet feeder

摘要

A retard roller of non-ground surface type which is virtually free from adhesion of paper dust thereby to have an excellent friction coefficient sustainability, 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 (10) and a sea portion (11) recessed from the island portions, the island portions and the sea portion each having a multiplicity of fine projections (12). The ratio S1/S2 of the total area S1 of the island portions to the area S2 of the sea portion preferably is 0.25 to 0.55. The fine projections preferably each have a height of 3 to 25 mum.