Patent ID: 7540496
Filing Date: 2009-06-02
Classification: B65H,G03B

Abstract:
1. A sheet carrying device for carrying a sheet along a passage, said sheet carrying device correcting a skew of said sheet relative to a carrying direction thereof while carrying said sheet, said sheet carrying device comprising: a skew corrector for correcting the skew of said sheet by making passage lengths different at both ends of said passage in a width direction thereof; a first carrying roller pair included in said skew corrector, where the first carrying roller pair is located at a curving portion of said passage; a second carrying roller pair located at a planar portion of said passage; carriers disposed at upstream and downstream sides of said skew corrector to carry said sheet along said passage; the skew corrector for performing one of removal and reduction of a carrying force to be applied to said sheet by said upstream carrier; and a controller for controlling said first carrying-force changer skew corrector after an anterior end of said sheet has reached said downstream carrier and a carrying force has been applied to said sheet, wherein said skew corrector tilts the first carrying roller pair from a reference position, which is parallel to the width direction of said passage, on a plane perpendicular to said passage to make said passage lengths different at both ends of said passage in the width direction and switching a first roller of said first carrying roller pair between a nip state and a nip-force releasing state, wherein a protrusion amount of a first roller of the second carrying roller pair is greater than a protrusion amount of a second roller of the second carrying roller pair, where a protrusion amount is a distance between a guide member and a nip surface of a roller that the nip surface of the roller protrudes the distance into said guide member, and wherein a protrusion amount of the first roller of the first carrying roller pair located at the curving portion of said passage is smaller than the protrusion amount of the first roller of the second carrying roller pair located at the planar portion of said passage.