1. An image forming apparatus, comprising: a controller unit configured to control an operation of, and/or input or output of data with, at least a printer unit and a scanner unit responsive to instructions from an application; an application management unit configured to detect a restricted function of which use by a given user is inhibited from among a plurality of functions within the application; and a function monitoring unit configured to register the restricted function detected by the application management unit, intercept instructions sent from the application to the controller unit, determine whether an intercepted instruction requests the restricted function, and responsive to determining that the intercepted instruction does request the restricted function, inhibit the user from executing the restricted function.