Patent ID: 8150291

Claim:
A power management system for managing power of a plurality of image forming apparatuses, comprising: a plurality of user terminals used by users of said plurality of image forming apparatuses; a detecting portion for detecting increase or decrease of the number of user terminals that are being used among the plurality of user terminals; a first determining portion for determining whether a change of power state of any of said image forming apparatuses is necessary or not, when the number of user terminals that are being used increased or decreased; a second determining portion for determining an object image forming apparatus, when change of power state is determined to be necessary; a changing portion for changing the power state of said object image forming apparatus; and a wearout degree obtaining portion for obtaining wearout degree of each of said image forming apparatuses, based on operation history of said plurality of image forming apparatuses; wherein said second determining portion determines said object image forming apparatus such that said plurality of image forming apparatuses come to have balanced wearout degree, based on said wearout degree, and said second determining portion includes a part for extracting candidate image forming apparatuses of which power state is to be changed, in response to increase or decrease of the number of user terminals that are being used, a part for determining as said object image forming apparatus, that one of said candidate image forming apparatuses of which wearout degree satisfies a prescribed condition, and a part for calculating, when none of said candidate image forming apparatuses has said wearout degree satisfying said prescribed condition, priority based on said wearout degree of each of the image forming apparatuses, and for determining the image forming apparatus having the highest priority to be said object forming apparatus.