Simultaneous recto-verso printing press

A recto-verso printing press adapted to carry out simultaneous recto-verso printing of sheets, the printing press comprising a main printing group with first and second printing cylinders cooperating with one another to form a first printing nip between the first and second printing cylinders where first and second sides of sheets are simultaneously printed, the first printing cylinder acting as a sheet conveying cylinder of the main printing group,

• wherein the printing press further comprises an additional printing group with third and fourth printing cylinders cooperating with one another to form a second printing nip between the third and fourth printing cylinders where the first and second sides of the sheets are simultaneously printed, the third printing cylinder acting as a sheet conveying cylinder of the additional printing group,
• and in that the main printing group and the additional printing group are coupled to one another by means of an intermediate sheet conveying system comprising one or more sheet-transfer cylinders interposed between the first and third printing cylinders,
• wherein the main printing group further comprises:
• a first set of plate cylinders cooperating with the first printing cylinder and which are inked by a first set of inking apparatuses;
• and
• a second set of plate cylinders cooperating with the second printing cylinder and which are inked by a second set of inking apparatuses,
• and wherein the additional printing group further comprises:
• a third set of plate cylinders cooperating with the third printing cylinder and which are inked by a third set of inking apparatuses;
• and
• a fourth set of plate cylinders cooperating with the fourth printing cylinder and which are inked by a fourth set of inking apparatuses.