Sheet thickness detector and image forming apparatus including same

摘要

A sheet thickness detector incorporated in an image forming apparatus includes a sheet conveying member to rotate and convey a sheet in a sheet conveyance direction, a driven sheet conveying member to contact the sheet conveying member and form at least one first transfer nip therebetween in a lateral direction and to displace by an amount equivalent to a thickness of the sheet passing through the first transfer nip and rotated with the sheet conveying member in the sheet conveyance direction, a displacement member to contact the sheet conveying member and form a second transfer nip smaller than the first transfer nip in the lateral direction and to displace by an amount equivalent to the thickness of the sheet passing through the second transfer nip and supported at a support member, and a displacement amount detector to detect an amount of displacement of the displacement member.

主权项

1. A sheet thickness detector comprising:
at least one sheet conveying member configured to rotate and convey a sheet in a sheet conveyance direction; at least one driven sheet conveying member configured to contact the at least one sheet conveying member and form at least one first transfer nip there between, the at least one driven sheet conveying member being biased to displace by an amount equivalent to a thickness of the sheet passing through the at least one first transfer nip, the at least one driven sheet conveying member rotating about a stationary rotary shaft and a movable rotary shaft in the sheet conveyance direction; a first displacement member configured to rotate about the movable rotary shaft and form a second transfer nip at a point of contact with the at least one sheet conveying member, the second transform nip being smaller than the at least one first transfer nip in the lateral direction, the first displacement member being biased to displace by an amount equivalent to the thickness of the sheet passing through the second transfer nip; a first support member having a free end, at which the first displacement member is supported; and a displacement amount detector configured to detect the amount of displacement of the first displacement member.