| 摘要 |
A sheet transport apparatus capable of applying a predetermined force for transporting any kind of paper, including a sheet of thin paper, without forming transport wrinkles in the paper caused by a nipping pressure. The apparatus includes a hard roller 114 and a soft roller 112 for nipping a sheet of paper 10 therebetween. The soft roller is driven to transport the sheet using a frictional force generated from the nipping pressure applied by the soft and hard rollers. The hard roller is in a barrel-shape having a predetermined radial curvature "R", such that the nipping pressure decreases gradually along its axis from the center toward the periphery of a nipping face between two rollers. This causes a compressive stress against the sheet to shift smoothly from a portion of the sheet nipped by the soft and hard rollers to a portion free from the nipping pressure. Thus, the formation of transport wrinkles in the sheet can be prevented.
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