In 1993, at an IS&T Symposium, Lucien De Schamphelaere explains the workings of the Xeikon DCP-1 press. Even more interesting is how he first describes in much detail the process of developing this press from scratch and the choices of basic technology made in the first few months after the start of the project in 1988.
‘Focus on a Digital Future’. The Society for Imaging Science and Technology (IS&T) could not have picked a better motto for its third ‘IS&T Technical Symposium on Prepress, Proofing & Printing’. The timing could not have been better either. The event was staged at Hotel in Chicago, Illinois (USA), from October 31 to November 3, 1993 – just one month after Indigo and Xeikon presented their ‘digital printing in full colour’ for the very first time at Ipex in Birmingham (UK).
IS&T started out in 1947 as the Society of Photographic Engineers, with the goal to publish scientific papers in the area of photographic engineering. In 1992, the name changed to the Society for Imaging Science and Technology, which has remained a rich source of information and knowledge on techniques, processes, and systems for imaging up until today.
With its symposium on prepress, proofing and printing in 1993, IS&T offered a broad program that perfectly captured the rise of digital technology in every aspect of the graphic arts industry. Accompanying the symposium was a book representing the program, containing technical papers from its presenters. Subjects vary from ‘A color to colorant transformation for a seven ink process’ and ‘Photo CD applications in professional prepress’ to ‘Large format imagesetters: issues, problems and solutions’ and ‘Filmless Rotogravure’.
Old and new
Rolf Demmerle from Heidelberger Druckmaschinen can be found describing how Direct Imaging technology is blending the old and the new – “connecting print to the information age”. The GTO-DI, developed by Heidelberg and Presstek in 1991, “is the logical connection between the electronic prepress and the printed sheet”.
A little further in the book, Yehuda Niv from Indigo explains ‘Indigo’s digital offset color: How it works’. “The heart of the press is an ElectroInk based liquid electrophotographic offset engine”, Niv writes. The article is accompanied by a schematic diagram of the recently announced E-Print 1000 and pictures that show ElectroInk producing superior halftone dots and line-work compared to offset and ‘powder toner’.
Inserted right between the articles from Heidelberg and Indigo is a 12-page segment, printed “on an industrial prototype of the Xeikon DCP-1”. It has Lucien De Schamphelaere, founder of Xeikon, explaining the workings of the press and its capability of ‘single pass digital color printing in duplex’. But what is even more interesting is how he first describes in much detail the process of developing this press from scratch and the choices of basic technology that were made in the first few months after the start of the project.
Electrophotography versus ion deposition
“Early 1989, a small group of technologists and scientist started the development of a product that would make quality color printing economically feasible, also for short runs”, writes De Schamphelaere. They considered various image recording technologies. ‘Inkjet with moving head’ was deemed ‘too slow’ and ‘inkjet with static array’ had not proven its reliability yet. ‘Laser addressed sublimation transfer’ needed ‘too expensive consumables’. Electrophotography was selected as ‘best fit’, but only after they ‘very seriously’ considered ion deposition: “We even developed a labmodel of a 4 color press based on a proprietary ion deposition array. We were able to print very pleasing tone images, but we could not meet the standards for text quality of the graphic arts industry.”
Dry or liquid toner?
Next came the choice of ‘electro-optic light pattern generators’. Xeikon opted for LED arrays, after finding laser beams and light valves based on deformable mirror devices not suitable for obtaining the required ‘high positional accuracy’.
For its electrostatic ink, Xeikon decided for ‘dry toner’ as “the best choice to base the further development of our machine on” – but only after seriously considering the use of liquid toners, according to De Schamphelaere. Not only did Xeikon’s ‘outside partner’ (De Schamphelaere does not name Agfa in the article) at that time “divide its R&D efforts between liquid toners and bi-component dry toner”, but the Xeikon-technologists “were also watching with great interest the results of development work on liquid toner at Coulter, Stork, Research Labs of Australia, Eastman Kodak, Indigo, AM Graphics and DX-Imaging”.
Multiple station, reel fed
For the configuration of the actual machine, Xeikon looked at four options: ‘single station - multiple pass’ or ‘multiple station - single pass’, and ‘sheet-fed’ or ‘reel fed’. “We have chosen for a multiple station, reel fed configuration”, explains De Schamphelaer. “The most important advantage of the multiple station concept is that, given a certain process speed, the speed of a four color press based on this concept is at least four times the speed of a multiple pass machine”. Reel feeding offers various advantages over a sheet-fed system: it guarantees better registering, permits non-contacting fusing, allows printing of images with a bleed, and enables the use of lighter paper.
The final problem that needed to be solved was the configuration of the duplex printing. Simply connecting two identical simplex presses with a web turning mechanism in between them, has two disadvantages: “its length, and the fact that two fusing systems are needed’. Also, the web needs to be reconditioned before it enters the second press-segment to avoid registration problems due to the loss of moisture in the first segment. De Schamphelaere also shows a scheme that solves the footprint problem and takes out the web turning mechanism, by stacking two simplex presses on top of each other. It does, however, still need two fusing units and “the paper supply or the paper output may be at an inconvenient height”.
It is only when the engineers come up with the idea of an integrated vertical configuration, that the distinctive Xeikon ‘tower design’ is able to meet the challenges. It is compact with a minimal web length inside the press and it has only one (double-sided) fusing system – together also improving registration. The vertical structure also allows for improved accessibility during servicing.
Making it happen
Lucien De Schamphelaere concludes his article for IS&T by thanking investors in Xeikon and the Flemish Government for trusting “entrepreneurs who at the start of the project had nothing to offer but a rather vague and incomplete picture of a new market, a new product and some new technologies.” “My special gratitude goes to the Xeikon team, to the hard-working people who made it happen. Without their professional skills and their extreme dedication, the project would have been impossible. It was and still is a great pleasure to work with them.”