A security printing press with at least one printing assembly having a printing unit, through which a sheet printing material at at least one printing point (06, 07) formed between a screen cylinder and an impression cylinder can be printed according to a screen printing process, having one or more drying devices (14, 16) on a printing material path downstream from the printing assembly and having a squeegee device comprised by the printing unit, comprising - screen printing form (31; 32), - squeegee, which is positioned in an on position ("AN") against the screen printing form (31; 32) or which can be positioned in an on position ("AN") against the screen printing form (31; 32), - bearing device (56, 57, 58) facilitating a throwing-on and throwing-off movement between the thrown-on position ("AN") of the squeegee and a thrown-off position ("AB"), - and a drive device (39, 41, 48) by means of which the squeegee can be positioned on and off by said drive device in operation correlated to a machine and/or printing-material phase position to the screen printing form (31; 32), characterized in that - an inking aid is provided, by means of which an opening located on the lateral surface of the impression cylinder of a groove comprising a holding device for printed sheets can be at least partially covered temporarily at least in the trailing region of the opening, and which facilitates a premature positioning of the lifted off squeegee in the event of nip entry of the open region of the opening, - that the drive device (39, 41, 48) comprises a drive means controllable by means of a controller, by means of which the throwing-on and throwing-off movement of the squeegee can be brought about mechanically independently from the machine and/or printing-material phase position and/or is brought about, and is equipped to bring about and/or facilitate a throwing on and throwing off of the squeegee in sequences differing from one another with different phase positions and/or phase lengths with respect to the length of the screen printing form (31; 32). - screen printing form (31; 32), - squeegee, which is positioned in an on position ("AN") against the screen printing form (31; 32) or which can be positioned in an on position ("AN") against the screen printing form (31; 32), - bearing device (56, 57, 58) facilitating a throwing-on and throwing-off movement between the thrown-on position ("AN") of the squeegee and a thrown-off position ("AB"), - and a drive device (39, 41, 48) by means of which the squeegee can be positioned on and off by said drive device in operation correlated to a machine and/or printing-material phase position to the screen printing form (31; 32), characterized in that - an inking aid is provided, by means of which an opening located on the lateral surface of the impression cylinder of a groove comprising a holding device for printed sheets can be at least partially covered temporarily at least in the trailing region of the opening, and which facilitates a premature positioning of the lifted off squeegee in the event of nip entry of the open region of the opening, - that the drive device (39, 41, 48) comprises a drive means controllable by means of a controller, by means of which the throwing-on and throwing-off movement of the squeegee can be brought about mechanically independently from the machine and/or printing-material phase position and/or is brought about, and is equipped to bring about and/or facilitate a throwing on and throwing off of the squeegee in sequences differing from one another with different phase positions and/or phase lengths with respect to the length of the screen printing form (31; 32).