To maintain the comfort of a network environment and to reduce the cost in printing standard-size form data in large quantity.

This print processing unit comprises computers 2a, 2b and a printer 3 that are connected thereto through LAN1. The computers 2a, 2b have print utilities that transmit a registration command for registering the data of print object to the printer 3 through LAN1. The printer 3 has a library 33 for storing the data of print object and a control part 32, which discriminates a command received through LAN1, for instance, if the command is the registration command, searches the library 33 for designated data, if there is no designated data, registers the data received from the computers 2a, 2b with the library 33, and then, using a received print command, reads the corresponding data from the library 33 to print the data with a print mechanism 34.