Image forming apparatus and method including power state shift control

Abstract

An image forming apparatus which is capable of achieving both enhanced userfriendliness and improved energy saving efficiency without being released from a reduced power consumption state by a user who has no will to use the same passing thereby. When a copying machineis in a sleep mode, it is detected whether or not a user has come near to the copying machine. If a contactless ICis present within the range of radio wave signals emitted from an IC tag reader/writer, it is determined that a user has come near because the communication between the contactless ICand the IC tag reader/writecan be carried out. Reading of data from the contactless ICis started, and user authentication is executed based on the data. If, as a result of the user authentication, the user is a licensed user, it is determined whether or not an original document has been set on an automatic feeder. When an original document has been set on the automatic feeder, the copying machineis caused to return to a normal mode as a normal power consumption state from the sleep mode.