In recent print shows, the Indigo Division of HP has introduced new presses based on the new BID development system, the fastest digital color printing products in the industry and with photographic quality capabilities for the high end photo market. “Digital Offset Color” is a process combining HP's unique electrically-responsive ink, “ElectroInk”, with a specially-developed thermal transfer process and a fast color switching technique. These are complemented by an ultra-high performance multi-beam laser scanner and unique image processing software. Pumping through the heart of HP's Indigo digital press is its propriety ElectroInk. ElectroInk enables these liquid electrophotographic printing presses to deliver prints of true offset quality. Only one to two microns in size, charged ElectroInk particles form highly defined characters, line work and halftone dot patterns. The “look and feel” of offset is achieved by a combination of ElectroInk's high saturation and extended color gamut and its unique ability to replicate the surface gloss of the underlying paper stock. The very small particles form extremely thin ink layers, less than one micron thick, enabling both high quality and low cost. Latent image formation, Binary Ink Development, and thermal offset transfer are discussed.
Udi Chatow, "The Fundamentals of HP Indigo's Digital Offset Color Printing Process and How It Rivals Mechanical Offset Printing" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP18), 2002, pp 125 - 129, https://doi.org/10.2352/ISSN.2169-4451.2002.18.1.art00030_1