Security Printing Deterrents: A Comparison of Thermal Ink Jet, Dry Electrophotographic, and Liquid Electrophotographic Printing

Security printing is the use of variable data printing (VDP) to add readable information to printed regions. This is used for brand identification, track and trace, product authentication, and, if applicable. for investigation and evidentiary purposes. Well-crafted, multiregion deterrents can be a powerful means to simultaneously provide readable information and deter would-be counterfeiters through the crafting of difficult-to-reproduce printing effects. This allows the brand owner to select the best printing technology for the deterrents (or for different aspects of a multiregion deterrent), and to gain insight into how the counterfeiter may attempt to reproduce their deterrent with a different printing approach. In this article. repeated line patterns, two-dimensional (2D) bar code reading, and authentication of a color deterrent (color tile) are considered. These features are printed using thermal inkjet (T/J), dry electrophotography (DEP). and liquid electrophotography (LEP) digital printers. Line patterns and 2D bar code differences are representative of the printer's binary print quality. Color tiles are representative of the printer's ability to produce color-based deterrents with fidelity, and are also used to show authentication accuracy on multiple printers and on multiple substrates. Authentication of TO printed color tiles is better on glossy paper than on plain office paper, whereas the opposite was observed for DEP printed color tiles. Finally, meaningful metrics for comparison are discussed, including security payload density, deterrent reproducibility. color and spatial frequency fidelity, deterrent precompensation. and the sensitivity of deterrent authentication to image capture settings