A process provides for the safe operation of a printing machine. The printing machine has a first cylinder driven by a first motor, and a second cylinder driven by a second motor. The first cylinder accepts sheets of paper from the second cylinder or delivers them to the second cylinder by a gripper system. In the case of a deviation in the synchronized running between the cylinders, the gripper system is retracted at least in part far enough into the first cylinder that the possibility of a collision of the gripper system with the second cylinder is eliminated.