Cylinder for aligning magnetic or magnetizable particles contained in coating agent on a substrate and machine for generating optically variable image elements

A cylinder (26) for aligning magnetic or magnetizable particles (P) contained in a coating agent (06) on a substrate (02), the cylinder comprising, in a region of an outer circumference thereof in a matrix-like manner, a number of n×m (where n and m are integers greater than one) magnetic elements (24) that provide magnetic fields, and which are arranged in n rows extending in an axially parallel manner and in m columns extending in a circumferential direction, and which, in the circumferential region, comprises suction elements (34) with suction openings (42) pointing outwards, characterized in that a plurality or all of the magnetic elements (24) that are arranged one behind the other are in each case combined with at least one assigned suction element (34) in respective modular units (36) as action units (36) in a plurality or all of the columns of magnetic elements (24), and as such can be positioned as a whole and in each case independently of all other such action units (36) in the circumferential direction and/or can be detached from the cylinder (26).