Image processing system, image processing apparatus and image processing method

An image processing system includes: a document storage apparatus for storing document data therein; an image processing apparatus connected to the document storage apparatus via a network, for processing the document data in association with the document storage apparatus; a first authenticator for performing user authentication at the time of an access to the document storage apparatus; a second authenticator for performing user authentication at the time of an access to the image processing apparatus; and controller for controlling, based on an authentication result by at least one of the first authenticator and the second authenticator, an authenticating operation by the other authenticator.