An illuminator for a traveling scanner of a document scanning system is disclosed. The illuminator comprises an elliptic-cylindrical surface of about one-half an ellipse in section with a line light source lamp located on one elliptic focal line. The illuminator is positioned so that the line of a document being copied is located at the other elliptic focal line. A reflecting cylindrical light baffle is positioned over the lamp to reflect light that would otherwise not strike the elliptical reflecting surface back through the source and onto the elliptical reflecting surface. The open end of the ellipse is covered with a heat filter to protect the material being copied. The ellipse is set at a relatively small angle, and a perpendicular reflection of material from the document being copied passes through a slot in the heat filter and a slot in the base of the ellipse for further sensing.