Sheet feed roller

Abstract

A less expensive sheet feed roller of a non-ground surface type for use as a pickup roller or a sheet feeding roller in a sheet feeder. The sheet feed roller is virtually free from adhesion of paper dust during use thereby providing an excellent friction coefficient sustainability. The sheet feed roller comprises a roller body and a shaft extending axially through the roller body, 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 S 1 /S 2 of the total area S 1 of the island portions to the area S 2 of the sea portion preferably is 0.25 to 0.70. The fine projections preferably each have a height of 3 to 25 μm.

What is claimed is:  
     
         1 . A sheet feed roller (except for a retard roller) for use in a sheet feeder, the roller comprising a roller body and a shaft extending axially through the roller body, 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.  
     
     
         2 . A sheet feed roller as set forth in  claim 1 , wherein a ratio S 1 /S 2  of a total area S 1  of the island portions to an area S 2  of the sea portion on the roller surface is 0.25 to 0.70.  
     
     
         3 . A sheet feed roller as set forth in  claim 1 , wherein the fine projections each have a height of 3 to 25 μm.  
     
     
         4 . A sheet feed roller as set forth in  claim 2 , wherein the fine projections each have a height of 3 to 25 μm.  
     
     
         5 . A sheet feed roller as set forth in  claim 1 , wherein the island portions on the roller surface each have a height of not smaller than 10 μm, and are spaced from each other by a peak-to-peak distance of not greater than 1.0 mm.  
     
     
         6 . A sheet feed roller as set forth in  claim 2 , wherein the island portions on the roller surface each have a height of not smaller than 10 μm, and are spaced from each other by a peak-to-peak distance of not greater than 1.0 mm.  
     
     
         7 . A sheet feed roller as set forth in  claim 3 , wherein the island portions on the roller surface each have a height of not smaller than 10 μm, and are spaced from each other by a peak-to-peak distance of not greater than 1.0 mm.  
     
     
         8 . A sheet feed roller as set forth in  claim 4 , wherein the island portions on the roller surface each have a height of not smaller than 10 μm, and are spaced from each other by a peak-to-peak distance of not greater than 1.0 mm.