Methods and Apparatuses for Creating Authenticatable Printed Articles and Subsequently Verifying Them

A printer with integral scanner obtains a digital signature from an article as it is printed. The integral scanner has a coherent source which directs a light beam to illuminate the article and a detector arrangement to collect data points from light scattered from many different parts of the article to collect a large number of independent data points. The digital signature derived from the data points is stored in a database with an image of what was printed on the article. The authenticity of an article purported to be the originally printed article can be verified by scanning the purported genuine article to obtain its digital signature. The database is then searched, to establish whether there is a match. If a match is found, the image is displayed with the matched digital signature to allow a further visual check that the article is genuine.