Patent ID: 8561160

Claim:
An authentication system, comprising: a single authentication information input device for multiple image forming apparatuses, the authentication information input device including an authentication information input unit, a display, and a first communication unit, the authentication information input device being a device through which a user inputs authentication information; an authentication server including a second communication unit, an authentication unit, and a specifying unit, the second communication unit being configured to acquire the authentication information from the first communication unit of the authentication information input device and the authentication unit is configured to perform user authentication based on the authentication information; and multiple image forming apparatuses, each including a receiver and an apparatus controller, wherein the authentication information input device, the authentication server, and the multiple image forming apparatuses are connected to each other via a network, the specifying unit being executable by a controller of the authentication server and configured to specify at least two image forming apparatuses among the multiple image forming apparatuses based on the authentication information, the second communication unit of the authentication server is configured to transmit a result of the user authentication indicating whether or not the user authentication is successful and information of the user identified by the authentication information to the at least two specified image forming apparatuses specified by the specifying unit of the authentication server, the receiver of the at least one specified image forming apparatus is configured to receive the result of the authentication and the user information transmitted from the authentication server, and the apparatus controller is configured to switch the image forming apparatus from an unusable state to a usable state according to the result of the user authentication and the user information, wherein the authentication server further comprises a notifying unit executable by a controller of the authentication server and configured to notify the authentication information input device associated with the image forming apparatus that the image forming apparatus is usable, when the authentication server receives a notice that the image forming apparatus is usable from the image forming apparatus, wherein the display of the authentication information input device is configured to visually indicate that the image forming apparatus associated with the authentication information input device is usable when receiving the notice that the image forming apparatus is usable from the authentication server.