Method of mounting and registering a printing plate on a plate cylinder of a multi-color offset printing press

A method of mounting and adjusting printing plates on plate cylinders of a multicolour offset printing press, the method comprising the following steps:

• a) clamping a leading end of a printing plate in a front clamping bar of one of the plate cylinders;
• b) wrapping the printing plate around the circumference of the plate cylinder;
• c) clamping a trailing end of the printing plate in a rear clamping bar of the plate cylinder, which rear clamping bar is movable under the application of a tensioning force and which rear clamping bar occupies, during the clamping of the trailing end of the printing plate in the rear clamping bar, a tension-release position;
• d) tensioning the printing plate by applying a nominal tensioning force to the rear clamping bar, thereby causing the rear clamping bar to move from the tension-release position to a nominal tensioning position;
• e) setting and storing the nominal tensioning position as a reference position of the rear clamping bar;
• f) measuring a print register of each tensioned printing plate once all of the printing plates have been clamped and tensioned on their corresponding plate cylinders;
• g) comparing the measured print register of each tensioned printing plate with a target print register and determining a corrected tensioning position of the rear clamping bar corresponding to the target print register for each printing plate;
• h) releasing the tension of the printing plate;
• i) setting the previously-determined corrected tensioning position as a new reference position of the rear clamping bar one of before and after tensioning again the printing plate;
• and
• j) if necessary, repeating steps f) to i) until the measured print register matches the target print register.