A security-papers printing press - having in the path of the printing material, at least a first printing site (06"), at which a printing material passing through said printing site (06") can be printed, in segments on at least a first of the two sides of said printing material in a cycle at a print image width with a cycle length (L Z) that is fixed in relation to the advancing of the printing material at the printing site (06"), with print images of a print image length that is shorter than the cycle length (L Z), - and a second printing site (07") that follows next downstream, at which the printing material passing through said printing site (07") can likewise be printed with print images on at least the second of the sides of the printing material, - and a dryer device having a dryer (14; 16; 36), which comprises a one- or multi-part radiation means and which is arranged in the printing material path between the first and the second printing sites (06";07") and/or in the printing material path following the second printing site (07") and by means of which radiation can be applied to the printing material passing through the dryer (14; 16; 36) on the transport path of the printing material in order to dry said printing material, characterized in that a control device that controls the drying means of the dryer (14; 16; 36) with regard to activation and deactivation is provided, which control device has a signal connection to a transmitter that provides signals (S K) representing the machine phase and/or the printing material progress and effects a switch-on and switch-off of the drying means or at least part of the drying means in each cycle in accordance with a sequence comprising at least one active and at least one inactive phase (P AN; P AB) in correlation with the machine and/or printing-material phase position, that the drying means of the dryer (14; 16; 36) is formed by an array of a plurality of adjacent radiation sources (38 k,i) extending over the maximum width of the printing substrate (B02 max), i.e. a number of at least 50 over the maximum width of the printing substrate (B02 max) and/or a length-related number of at least 50, preferably at least 70 adjacent radiation sources (38 k,i) per meter, in particular UV-LEDs, that a radiation zone is configured on a segment of the drying means which is formed by a group of jointly activating and deactivating radiation sources (38 k,i) and on both sides optionally reach to the respective end or on one or both sides are continued by one or more radiation sources (38 k,i) not involved in the sequential activation and deactivation, and that for the formation of a radiation zone of variable width and/or position radiation sources (38 k,i) variable to the group can be jointly combined to activating and deactivating radiation sources (38 k,i). - having in the path of the printing material, at least a first printing site (06"), at which a printing material passing through said printing site (06") can be printed, in segments on at least a first of the two sides of said printing material in a cycle at a print image width with a cycle length (L Z) that is fixed in relation to the advancing of the printing material at the printing site (06"), with print images of a print image length that is shorter than the cycle length (L Z), - and a second printing site (07") that follows next downstream, at which the printing material passing through said printing site (07") can likewise be printed with print images on at least the second of the sides of the printing material, - and a dryer device having a dryer (14; 16; 36), which comprises a one- or multi-part radiation means and which is arranged in the printing material path between the first and the second printing sites (06";07") and/or in the printing material path following the second printing site (07") and by means of which radiation can be applied to the printing material passing through the dryer (14; 16; 36) on the transport path of the printing material in order to dry said printing material,