Abstract: 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 (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 &mgr;m.

Abstract: The present invention provides a method for machining a workpiece, which comprises the steps of: separately supplying compressed air and a liquid into a through-hole longitudinally extending through a drawbar within a spindle of a machine tool; allowing the compressed air and the liquid to separately flow through the through-hole; mixing the liquid with the compressed air in a distal end portion of the through-hole so as to make the liquid into a mist form; ejecting the resulting mist from a distal open end of the through-hole to supply the mist to a distal end of a tool along an outer periphery of the tool or through the inside of the tool; and machining the workpiece while ejecting the mist from the distal end of the tool to supply the mist to a machining part.