A scanning apparatus for scanning a sheet as the sheet is transported in a substantially vertical transport direction. The scanning apparatus includes a scan housing; first, second, and third couplings; and a transport apparatus. The scan housing supports an optical scanning apparatus. The second and third couplings allow at least two degrees of rotation of the scan housing with respect to a horizontal axis and constrain movement of the scan housing in a substantially vertical transport direction. The transport apparatus is coupled to the scan housing for guiding the sheet past the scan housing in the substantially vertical transport direction.