Secure Printing via Selective NFC Device Information Exchange

The patent applies local quality by differentiating the response behavior of the printer based on the mobile terminal's identity. The printer selectively replies device-specific information only to authorized mobile terminals (those with matching device-specific information) while ignoring unauthorized ones. This localized differentiation resolves the contradiction by providing printing functionality to authorized devices while maintaining network security against unauthorized access.

The patent applies preliminary action by having mobile terminals pre-store device-specific information about the printer before attempting to print. This preliminary preparation enables the terminal to identify whether it is authorized to communicate with the printer. When the terminal sends a connection request, the printer can quickly determine authorization based on the pre-stored information, ensuring both network security and printing functionality without requiring complex real-time authentication processes.

The patent applies the intermediary principle by introducing device-specific information as a mediator between the mobile terminal and the printer. Instead of requiring full wireless communication establishment for authorization verification, the device-specific information acts as an intermediary credential that enables secure identification and connection. This mediator allows the system to maintain security while still enabling printing capability, as the terminal can use the stored device-specific information to establish targeted communication with the authorized printer without needing broad network connectivity.