Machine for mounting flexible printing plates on plate-holder cylinders of flexographic printing machines and for printing proofs

A machine for mounting flexible printing plates on plate-holder cylinders of flexographic printing machines and for printing proofs with the cylinders thus prepared, said machine comprising:

• a beam located at front region of the machine;
• supports being positionable along said beam;
• a plate-holder cylinder extending horizontally along a longitudinal axis thereof and being rotatably supported on said supports;
• a counterpressure drum being rotatably supported at said front region of said machine, parallely to said plate-holder cylinder;
• a sheet of paper having registration markings and covering said counterpressure drum,
• said beam and counterpressure drum being horizontally parallel, with said beam being vertically movable between a lower mounting position, for positioning and fixing printing plates, and a raised printing position, in which the printing plates make contact with the counterpressure drum;
• a bar lying parallel to and above said counterpressure drum;
• at least two sliders that are slideable and respectively lockable upwardly along said bar;
• respective small semitransparent mirrors, each of which is provided in a downward region of said sliders for allowing to align directly-viewed points of said plate-holder cylinder, in the mounting position, with reflected points of said paper sheet,
• video cameras being located each at a central region of a respective one of said sliders and directed towards the plate-holder cylinder, said cameras being placed in the mounting position, along axes that intersect said respective small semitransparent mirror and lying substantially at right angles to said axis of said plate-holder cylinder;
• front monitors being respectively connected to a corresponding one of said video cameras to form low-magnification systems;
• said bar being movable for oscillating between an active position in which said small semitransparent mirrors are lowered and arranged between the counterpressure drum and the plate-holder cylinder in the mounting position, and a proof printing position in which the semitransparent mirrors are raised in a spaced position.