Patent ID: 8112793

Claim:
An image forming apparatus, comprising: a searching section that reads image data and authentication data from a transportable external storage device detachably inserted into the image forming apparatus, wherein the transportable external storage device includes (i) a device ID information storing section that stores a first device ID value that identifies the transportable external storage device, and (ii) a file information storing section that stores the image data and the authentication data, the authentication data including a second device ID value and authentication information, wherein the second device ID value identifies a transportable external storage device into which the image data is originally stored, the second device ID value being stored into the file information storing section and being the same as the first device ID value when the image data is originally stored into the file information storing section; and an authenticating section that performs: (i) a first authentication to determine whether the first device ID value obtained from the transportable external storage device is the same as the second device ID value obtained from the transportable external storage device, and (ii) a second authentication by comparing the authentication information stored in the file information storing section of the transportable external storage device with authentication information received from a user from outside the image forming apparatus; wherein said searching section reads image data from the transportable external storage device only when the first authentication and the second authentication have been established.