Patent ID: 8269995

Claim:
An image forming apparatus for printing a confidential image on a recording medium, comprising: a display; a printer for printing images in a queue; a storage for storing fingerprint data of each user as reference data; an input for receiving fingerprint data for a user; a timer for counting a first specified time interval and a second specified time interval shorter than the first specified time interval, the timer starting when the printer starts printing a confidential image; and a processor for determining whether the fingerprint data from the input corresponds to the reference data in the storage by (i) calculating a degree of similarity between the fingerprint data from the input and the reference data, and (ii) determining whether the degree of similarity is more than a first threshold value or a second threshold value, and for enabling the printer to print the confidential image if the fingerprint data from the input corresponds to the reference data in the storage; wherein the display prompts the user to re-enter the fingerprint data for the user when the timer has counted the second specified time interval and while the printer prints the confidential image, wherein the processor disables the printer from printing confidential information if the input does not receive re-entered fingerprint data from the user that corresponds to the reference data in the storage within the first specified time interval, and resets the timer when the processor determines that the re-entered fingerprint data from the input corresponds to the reference data in the storage, and wherein the second threshold value used for determining whether a degree of similarity between the re-entered fingerprint data and the reference data is more than the second threshold value is lower than the first threshold value used for determining whether the degree of similarity between initial fingerprint data and the reference data is more than the first threshold value, so as to make a successful personal authentication for the re-entered fingerprint data by the processor easier.