A hinge apparatus for a cover of an image forming apparatus has a hinge body with supporting brackets, movably inserted into a coupling hole positioned in a main body of the image forming apparatus, a hinge cam connected to the cover and pivotably connected to the supporting brackets, and a pressure device disposed at the hinge body to press the hinge cam. The lower-order bits of the output data from the selector 62 are processed through expanded transposition and then are calculated together with key data K1 in an XOR circuit, and the result data are latched according to a clock CLK2. A user can access the adjusted copy of the resource from a device connected to a network, such as the Internet, to display the link usage data with each associated link.