PURPOSE: To detect the number of residual sheets correctly so as to use a printer efficiently.

CONSTITUTION: Work stations 12 and printers 11 are connected through a local area network. The whole local area network is controlled by a file server 11, and each printer 16 is controlled by a print server 19. A residual quantity computing means is disposed at each printer 16 so as to compute the residual quantity of sheets. The status of each printer 16 including the residual quantity of sheets is transmitted to the file server 11 and stored in a sheet residual quantity register. The stored sheet residual quantity is displayed on the display of each work station 12. A user can thereby confirm the state of the printers 16 before executing a printing job.