To display the kinds of troubles and a means which should be introduced when troubles occur by enabling a control section to generate a further signal in addition to a command signal for a trigger of a work step preset for replacing a press plate.

After a signal is inputted into printing units 6.1 to 6.6, which should replace a press plate, through a data input means 8 in a control console computer (calculating device) 1, the corresponding data are transferred from the computer 1 to a control section 2 for controlling the process of replacement through a bus system 4, and the printing unit correspondingly selected is displayed on an indicator 7 with a corresponding display marking. During the execution of the replacement process based on the inputted preselection at the printing units 6.1 to 6.6, the control section 2 produces a command signal to be sent to input/output units 2.1 to 2.6 and generates a state signal of additional information through the bus system 4 for the trigger and practice of the process for replacing the press plate at the printing units 6.1 to 6.6, and the state signal is received by the computer 1 to be displayed on the indicator 7 as information.