Printing press with in-line casting device for the replication and formation of a micro-optical structure

A sheet-fed printing press adapted to carry out printing on individual sheet-like substrates for the production of bank notes, the printing press comprising:

• a sheet-like polymer substrate with an opaque portion and a transparent portion, the substrate comprising:
• a first side;
• and
• a second side opposite the first side, the transparent portion extending from the first side to the second side;
• a substrate feeding device configured to feed the substrate;
• a delivery unit configured to receive the substrate;
• an in-line casting device adapted to apply a layer of material acting as an optical medium directly on the second side of the substrate at the transparent portion and adapted to replicate and form a micro-optical structure in the optical medium on the second side of the substrate, the opaque portion of the substrate remaining uncovered by the layer of material acting as an optical medium and the in-line casting device being located in a conveying path for the substrate between the feeding device and the delivery unit;
• at least one drying/curing unit configured to dry or cure the layer of material acting as the optical medium following replication of the micro-optical structure in the layer of material acting as the optical medium, the at least one drying/curing unit being located to dry or cure the layer of material acting as the optical medium from the second side of the substrate;
• a printing unit configured to print on at least the first side of the substrate, the printing unit being located in the conveying path for the substrate between the feeding device and the delivery unit and comprising:
• a first printing group comprising a printing cylinder, the first printing group being adapted to print at least one printed pattern directly on the first side of the substrate in register with the micro-optical structure;
• a transfer mechanism configured to transfer the substrate from the in-line casting device to the printing unit, the transfer mechanism comprising a first transfer cylinder downstream of the in-line casting device, the transfer mechanism being configured so that the transfer of the substrate between in-line casting device and the printing unit is carried out exclusively from cylinder to cylinder via cooperating cylinder grippers;
• and
• a washing device that is configured to be selectively brought into contact with the at least one embossing cylinder during maintenance operations to clean the surface of the at least one embossing cylinder,
• wherein the first printing group is a collect printing group configured to collect at least two imprints before printing the at least two imprints onto the substrate,
• wherein the in-line casting device comprises at least one embossing cylinder configured to act as a carrier supporting a replicating medium designed to replicate and form the micro-optical structure in the layer of material acting as the optical medium and/or act as a conveying cylinder carrying and/or supporting the substrate over an angle range,
• wherein the at least one drying/curing unit is located about a portion of the circumference of the first transfer cylinder located immediately downstream of the at least one embossing cylinder, and
• wherein the first side of the substrate is opposite the second side of the substrate.