Automated transaction system with modular printhead having print authentication feature

In a transaction terminal having input means for inputting a request for printing a value indicia on an article, printing means for printing the requested value indicia on the article, and operating means for operations said terminal to enable a user to input the request for value indicia through said input means and to enable said printing means to print the requested value indicia on the article, an improved printing means for said transaction terminal comprising:

• said printing means being formed as a separate section in said terminal and having a printhead and a dedicated microprocessor for controlling said printhead contained therein;
• first ink supply means for supplying a visible ink to said printhead;
• second ink supply means for supplying an invisible, machine-readable ink to said printhead;
• and
• said printhead microprocessor having interface means connected to said operating means of said terminal for receiving the value indicia request input to said terminal, and print program means for controlling said printhead to print the requested value indicia as a visible indicia with visible ink from said first ink supply means on said article, for deriving an authentication code which uniquely corresponds to the requested value indicia, and for controlling said printhead to print the authentication code as an invisible indicia with invisible ink from said second ink supply means on said article, whereby said printed visible value indicia can be subsequently verified as authentic by machine reading of said invisible authentication code and comparing the authentication code for correspondence to the value indicia.