Apparatus for control of printer

PROBLEM TO BE SOLVED: To make it possible to input a modified partial program and a corresponding parameter to a given computer by control of switching a computer connected to a bus by a bus interface from a normal mechanical operation state to a second state. SOLUTION: After corresponding computers 2.1-2.4 are addressed and switched to a programmable mode, data transmission from a programming device 5 is performed through a bus 1. A partial program and/or a parameter are transmitted from the programming device 5 through the bus 1 to a given computer 2.1-2.3 or a control station computer 2.4. After being intermediately stored in the addressed computer 2.1-2.3 or computer 2.4, the partial program and/or the parameter are written into the corresponding non-volatile rewritable memory 3.1-3.4.