A digital copying machine is connected to at least another one of digital copying machines with which data communications can be performed. The digital copying machine has a link copy function that a document is set in the machine itself or another digital copying machine and at least two units of the digital copying machines share the job of executing copy operation on the document, and a printer function of printing according to a print request from the outside. When receiving the print request from the outside during the copy operation based on the link copy function from its start to finish, the digital copying machine puts the print request on hold.