Reveal of reference marks for mounting of printing plates

A method for preparing lithographic printing plates for on-press development, comprising:

• from a supply of rectangular plates having short sides and long sides, a substrate, and an overlying, radiation polymerizable coating, sequentially feeding said plates to an imaging station to produce a plurality of latent image reference marks allocated among at least two margins along a respective two sides of the plate, and a latent print image within the margins;
• transporting the imaged plates from the imaging station to a plate bending station where the short ends of the plate are bent over;
• and
• between the imaging station and the bending station, removing unimaged areas of the coating in at least two of said margins to reveal the reference marks without developing the latent print image.

A method for preparing lithographic printing plates for on-press development, comprising:

• from a supply of rectangular plates having short sides and long sides, a substrate, and an overlying, radiation polymerizable coating, sequentially feeding said plates in a first transport direction to an imaging station in a portrait orientation whereby the long sides are parallel to the transport direction;
• at the imaging station, radiation imaging the coating to produce a plurality of latent image reference marks allocated among at least two margins along a respective two sides of the plate, and a latent print image within the margins;
• reorienting the imaged plates to landscape whereby the short sides are parallel to a second transport direction;
• transporting the imaged plates in landscape orientation in said second direction to a margin developing station;
• at the margin developing station, removing unimaged areas of the coating in said margins to reveal the reference marks, wherein the latent print image within the margins is not developed;
• feeding the plates with revealed reference marks R1, R2, R3 in landscape orientation to a bending station where the plates are bent in dependence on detection of the reference marks;
• mounting the bent plates to a plate cylinder of a printing press;
• and
• while the plate is mounted on the plate cylinder, developing the latent print image within the margins.