Though it has become the talk of the industry only fairly recently, single-pass inkjet printing goes back 20 years to a system that demonstrated the enormous potential of the technology.
“I saw the potential of PrintStreamer, but also the shortcomings of dry-toner digital printing for the markets we were serving,” says Rob Haak, who managed Barco’s digital printing division. “We started to study piezo drop-on-demand technology, and decided to move forward with plans to build a single-pass, full-color inkjet system using UV inks for the markets we knew and had already served. We knew how to feed and master the data streams for full-speed digital presses, so it was a logical step for us.”
In April of ’98, Haak approved plans to develop a single-pass, roll-to-roll system tentatively named Ramses that could be adapted for a variety of industrial applications. Among the key partners brought in for the project were Metronic, a German manufacturer of roll-to-roll systems for flexo printing that built the substrate transport system, and the UK firm Cambridge Consultants, which worked on the printhead array (known as the Single Pass Inkjet Color Engine, or SPICE). Barco, in addition to integrating the project, developed the front end technology including the RIP.
The touch-screen control panel was designed with a simple user interface.
Ambitiously, the partners set out to unveil their new single-pass technology at drupa 2000, then only 25 months away. “The schedule was quite compressed,” remembers Will Eve, who worked for Cambridge Consultants then and led the project. (He’s now director of technology for Inca Digital Printers.) “It was all quite new. We could see that it should be possible to put together wide systems using multiple printheads, and we knew that drop on demand was much simpler than continuous inkjet. What, as they say, could possibly go wrong?”
Well, a lot of things. The team would soon encounter the formidable hurdles to single-pass printing that continue to challenge inkjet developers to this day, not least of which is banding. It turned out that drop-on-demand machines used traversing heads for a reason: Without the redundancy of those overlapping passes, defects from clogged nozzles or printheads that weren’t uniform or in perfect alignment with one another were glaringly apparent. Other challenges included keeping the ink stable at such rapid deposition speeds and understanding the drop-on-drop interactions after jetting.
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