Security paper/document construction

Abstract

Security paper having a number of parallel lines having a substantially uniform first spacing, irregularly interrupted by a plurality of stripes having a second spacing greater than the first spacing, is flexographically printed on at least one face of a web which becomes, after further processing, a security document such as a bank check. The parallel lines typically are substantially straight and of substantially uniform thickness and formed of flexo ink, such as the type which becomes invisible when bleached. Alphanumeric indicia are preferably provided within the stripes either oriented parallel to the parallel lines (and alternately extending from top to bottom, and bottom to top), or perpendicular to the parallel lines. A pattern is provided that repeats at an interval significantly greater than the length of the security document formed from the security paper. At least one of the faces of the security document, typically the face opposite that having the parallel lines, has readable alphanumeric indicia appropriate for a security document imaged on it. The web on which the flexographic printing and imaging takes place is ultimately cut into individual security documents or sets of security documents, with the interval of a security pattern about 15-17 inches, and the length of the security document about 5.5-12 inches. The web may be taken up and shipped to another location after flexographic printing and tensioning to stretch the pattern, prior to imaging of the security document indicia.