A plurality of image forming apparatuses is connectable to a plurality of host apparatuses via a network. The image forming apparatus includes an apparatus information collection unit to obtain print history and function information as apparatus information of each image forming apparatus; a priority order determination unit to determine a priority order for setting a master image forming apparatus; a master determination unit to determine an image forming apparatus among the currently operating image forming apparatuses; a host information collection unit to collect print history and current print settings as host information of a power-ON host apparatus; a required-printing-capacity computing unit to compute required network printing capacity based on the host information; and a power save control unit to control the power save mode of each image forming apparatus. The power save control unit of the master image forming apparatus controls the power save mode of each image forming apparatus.