Most four-color printing processes that are extensively used in electrophotographic (EP) applications today are based on the SWOP (Specifications for Web Offset Publications) colorants. Although, this set of colorants offers many advantages, it fails in many aspects as it does not deliver many often requested colors in digital printing. For example, most corporate identity colors cannot be faithfully reproduced with the available gamut possible with this color set. Most attempts to increase the color gamut by selecting high chroma colorants only provides marginal improvements. At the same time these colorants can have high impact on toner performance developer life. Many of the limitation of a four color system can be addressed by a adding fifth module in the digital color press. One such digital press now commercially available, is NexPress 2100. By proper selection of fifth color DryInk™ or toner, and utilizing pentachrome process, Nexpress 2100 digital press manages to expand color gamut on demand while still continuing to utilize the standard CYMK toners. The result is a low cost solution to matching most colors that are often demanded by customers. With the availability of fifth module, it is also possible to use it to apply a clear overcoat in an intelligent manner. Such a coating process is truly inline and offers efficient workflow solutions. Clear Overcoats provides superior protection and enhance many image quality attributes. Many capabilities and limitations of fifth module will be presented. Impact on EP process and color gamut by the colorant selection will also be discussed.
Dinesh Tyagi, Peter Alexandrovich, Yee Ng, H.T Tai, Rich Allen, Diane Herrick, "Enabling Expanded Color Gamut and In-line Coating Processes" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP20), 2004, pp 135 - 138, https://doi.org/10.2352/ISSN.2169-4451.2004.20.1.art00034_1