Dust tolerant windowless scanner

A dust tolerant scanner without a transparent plate to support objects scanned by its media scan assembly. Other dust or debris collecting surfaces in the optical path of the scanner are positioned as far away as possible from an object focal plane of the media scan assembly. The media scan assembly includes upper and lower document feeder portions which define a media path adjacent to a reference surface of the upper portion. The lower document feeder portion includes a media conformance member which positions pieces of media against the reference surface as the pieces of media are advanced along the media path. The media conformance member includes ramp portions and an aperture which provides an optical path between the object focal plane and a sensor focal plane within the scanner.