Patent ID: 8854650

Claim:
A network printing system in which: a print server, an image forming device and a database are connected via a network; first certificate information issued by the image forming device is registered with the database in advance; and when the print server executes printing using the image forming device, second certificate information issued by the image forming device in response to a request is compared with the first certificate information issued by the image forming device and registered with the database, and the printing is started using the image forming device if the second certificate information matches the first certificate information, wherein the first certificate information is registered with the database as an entry associated with key information that serves as a key used in searching for the first certificate information, the print server stores the key information registered with the database in association with the image forming device, and when executing printing using the image forming device, transmits the key information associated with the image forming device together with the second certificate information received from the image forming device to the database and causes the database to compare the first certificate information with the second certificate information, the database compares the first certificate information identified by the key information with the second certificate information and transmits a result of comparison to the print server, and the print server starts printing using the image forming device in accordance with the result of comparison received from the database.