The Scalable Pipeline Architecture behind HP's T300 Color Inkjet Web Press

Abstract

The HP T300 Color Inkjet Web Press uses two identical print engines capable of printing full variable data at 400 fpm and 1200x600dpi on a 30” wide web. Each print engine prints four colors of ink (CMYK) and Bonding Agent (BA). Each of the five inks employs two print bars in tandem in an arrangement that provides nozzle redundancy. Each of the 10 printbar contains seven 4.25” thermal inkjet printheads with over ten thousand nozzles each. This massive array of nozzles consumes 35 Giga bits of nozzle firing data per second.The data flow starts with the Digital Front End which provides the interface to the press, processes job ticketing and decomposes incoming PDF files into small chunks that are then concurrently processed by a scalable array of raster image processors (RIPs) built on high-performance blade servers. This solution allows RIPs to be tailored to meet any demand required by a customer's print job.The raster images are then compressed and buffered before being delivered in print sequence order to the two print engines.The print engines partition the incoming raster images into bands called slices; each slice covers the width of one Printhead plus some overlap area. Image processing hardware runs in parallel for each slice transforming the compressed CMYK continuous tone raster into real time nozzle firing instructions.The result is a scalable image processing architecture that extends to wider presses by simply replicating the basic hardware building blocks across the web.