Patent ID: 7278704

Claim:
An image forming apparatus comprising: an image forming part that forms an image on a recording medium; a first measuring part that, downstream of the image forming part in a transport path of a recording medium, measures speckles on the recording medium in the transport path, and generates measured speckle data that represents speckles measured; a memory part that stores the measured speckle data generated by the first measuring part; a second measuring part that, upstream of the image forming part in a transport path of a recording medium, measures the speckles of the recording medium in the transport path; and a recognition part that determines whether or not speckle data representing speckles analogous to speckles measured by the second measuring part is stored in the memory part, and, in the case where the decision result is affirmative, recognizes that the recording medium for which the speckles have been measured by the second measuring part is a recording medium on which an image has been formed previously to having speckles measured by the second measuring part.