Abstract: A constant velocity transport for moving documents of various thicknesses at a uniform rate across the scan aperture of a raster input scanner employing one or more solid state arrays for scanning the document through the aperture line by line. A floating viewing element is disposed in the scan aperture with the document transport comprising a single feed roll disposed opposite the viewing element and in engagement therewith. The viewing element and the feed roll cooperate to form a nip between which the document being scanned passes. A pair of leaf springs bias the viewingelement into operative engagement with the feed roll while permitting various thickness documents to be fed. A controlled friction surface is provided on the viewing element at the point where contact between the feed roll and viewing element is established to obviate velocity perturbations in the feed roll resulting from changeover from a no document feed to a document feed state and vice versa.

Abstract: An electrostatographic type copying or reproduction machine incorporating a programmable digital computer to operate various machine components. The computer includes a memory which contains a plurality of different operating programs with each program instructing the machine to operate in a different manner. In one embodiment, one of the programs is utilized to produce copies, whereas other selectively accessable programs operate the machine components in such manner to diagnose machine malfunctions.