Stamp detection in a mail processing apparatus

摘要

A mail processing apparatus feeds mail articles one by one, along a transport path. A stamp detecting device is disposed along the path to detect a stamp on the mail article. The stamp detecting device includes a light source for radiating ultraviolet light towards both sides of the mail article in the transport path, and converters for converting the luminescences excited by the ultraviolet light on both sides of the mail article. Two signal levels are detected and compared for determining where the stamp is located. This way, a stamp does not appear to be on both sides of a very thin article.