Sheet thickness detector and image forming apparatus including same

The invention relates to a sheet thickness detector and an image forming apparatus including the same. A sheet thickness detector (40) incorporated in an image forming apparatus (1000) includes a sheet conveying member (41) rotating and conveying a sheet (P) in a sheet conveyance direction, a driven sheet conveying member (50, 52) contacting the sheet conveying member (41) and form at least one first transfer nip therebetween in a lateral direction and displacing by an amount equivalent to a thickness of the sheet (P) passing through the first transfer nip and rotated with the sheet conveying member (41) in the sheet conveyance direction, a first displacement member (60) contacting the sheet conveying member (41) and form a second transfer nip in the lateral direction and displacing by an amount equivalent to the thickness of the sheet (P) passing through the second transfer nip, and a displacement amount detector (44) detecting an amount of displacement of the first displacement member (60).