Examination of Counterfeit Banknotes Printed by All-in-One Color Inkjet Printers

An increasing number of cases related to counterfeit Hong Kong banknotes produced by all-in-one inkjet color printers have been encountered recently. Unlike those generated by color laser printers or photocopiers, characteristic dot patterns or irregularities are not present on counterfeit banknotes generated by color inkjet printers, thus creating difficulties in the identification of the printer. This paper describes the relationship between the counterfeit banknotes and printers seized in local clandestine factories. The conventional thin layer chromatography (TLC) method was employed to study the ink profiles of the inks present on the counterfeit banknotes and was found to be a useful tool for distinguishing different printer inks.