Patent ID: 7521075

Claim:
A sheet material for producing packages of food products and comprising a number of fold lines, and at least one optically detectable register mark; wherein said register mark comprises at least two parallel segments perpendicular to a feed direction of said material, the parallel segments allowing detection of the sheet material in a feed direction along which the sheet material is fed during production of the packages; and a sloping segment interposed between the parallel segments, the sloping segment allowing detection of the sheet material in a direction perpendicular to the feed direction, wherein said fold lines are compression lines having a recessed profile on a first face of the material and a nonconvex profile on a second face of said material, wherein each of said parallel segments forming a part of the optically detectable register mark is defined by at least a portion of one of said compression lines, and wherein the sloping segment forming at least a part of the optically detectable register mark is defined by at least a portion of one of the compression lines, the sheet material further comprising at least one printed area at least partly enclosing said compression lines and defining, with said compression lines and in contrast to said compression lines, said register mark.