Exemplary embodiments of the present invention provide a network data processing system to reduce traffic and time for the first printout. A client unit generates printing data, which is divided to correspond to respective constituent parts constituting printing contents, and transmits a printing request including header information to a printer. When the printing request is received, the printer analyzes the received printing request, determines whether partial data necessary for constructing the printing data are stored in a storage section, acquires missing partial data from a printer of which a hop count is smallest, stores the acquired partial data in the storage section, and then constructs the printing data on the basis of the partial data of the storage section. Furthermore, the printer retrieves a storage section for the partial data in response to an acquisition request and transmits the detected partial data to the printer.