At the recent Heimtextil show there was a whole hall dedicated to wallpapers and wall coverings and nestled amongst the various companies showing off wallpapers I came across Olbrich and its digital approach.
Derek Smith, Manager of Ricoh UK Product’s Technical Development and Engineering team.
Olbrich is one of the main European suppliers of wallpaper production lines. Jens Krebber, director of international business development and marketing for Olbrich, says: “Our main expertise is in the production component itself. But we supply a complete line including embossing, wrapping and labelling as well as energy recovery and calendering systems from third parties.”
Olbrich has partnered with Ricoh to develop an inkjet module that can be incorporated into its production lines. The two companies have further been working with Marburg, one of the major suppliers of wallpaper to the European market, to tailor this digital solution for real world production. To this end, Marburg has hosted a Ricoh unit on its Olbrich production line since May 2019.
The Ricoh unit is a single pass inkjet module based on Ricoh’s Gen5 printheads and can run at up to 70mpm at 600 dpi resolution. It uses an oil-based ink that’s produced at Ricoh’s plant in Stirling, Scotland. The advantage of the oil-based ink is that it doesn’t evaporate under normal conditions and there’s little danger of nozzles being clogged. Derek Smith, Manager of Ricoh UK Product’s Technical Development and Engineering team, says that some customers see inkjet as having a lot of maintenance issues, which these inks have overcome. He adds: “We want it to be a stable mass production process.”
The wallpaper itself is a conventional non-woven fleece-based substrate with a PVC overcoating, which gives good rub resistance and is easy to keep clean. The process starts with the fleece, then the inks are jetted, followed by the PVC, still in a liquid state so that it’s essentially a wet on wet process. Smith adds: “So when we cure the PVC we are assimilating the ink to the PVC so that it becomes part of the PVC. It’s not on the surface but part of the PVC itself.”
For now, it’s printing CMYK though there is room for up to six print channels. Smith says the extra channels could be used for additional colours or to add functional fluids or a coating. The Ricoh inkjet module has been retrofitted to an existing line so that Marburg can choose to use gravure or inkjet on any given print run. Smith points out that there’s also the potential for hybrid production, for example, combining a conventional metallic effect with digital print, that has not yet been explored.
Smith believes that digital wallpaper will become more common in the future, explaining: “The key advantage of inkjet is the manufacturing efficiency. You don’t have all the cost of the gravure cylinders, you don’t have the downtime associated with changing the gravure cylinders. The economic batch size is much smaller.” He says that customers will be able to print samples or one-offs according to demand as part of their day to day manufacturing, adding: “You have print on-demand so there’s no need to keep warehouses of stock.”
But he also points out that there’s a need to develop a corresponding web-to-print solution, saying: “It’s a great printing solution but a back office nightmare because you have to print and ship the rolls out, so it is different.”
Digital printing also allows for a completely new approach to artwork, which Krebber and Smith believe will help to rejuvenate the wallpaper market. Conventional wallpaper uses a repeating pattern, which is limited to the size of the gravure cylinders. This in turn has led to a standard size of 530 x 530mm. But there’s no repeat necessary with digital printing so that the artwork can be much more creative.
The Ricoh module prints at 600 dpi resolution and Krebber says that there’s no demand for higher resolution. Smith points out that this resolution is already better than most of the existing artwork, which is sometimes only 150 dpi, though he adds: “You do get an extra punch with a 600 dpi design.” Besides, he also explains that higher resolution would mean having to push more data to the printheads, which would also be a challenge, noting: “We are on the limit of data capability and that’s one of the limitations of inkjet so the computing power is having to catch up with the inkjet technology.”
The other challenge is that the wallpaper market is extremely cost-sensitive and unwilling to take risks. Smith points out that there’s also a surprisingly high number of certifications and ecological labels that have to be maintained, adding: “So we wanted to develop something that would fit into the market and not reinvent it.”
The system is still officially being beta tested, though Marburg showed off a number of wallpapers at Heimtextil that had been printed on this line. Apart from the design freedom of getting away from repeating patterns, there was nothing about these samples to suggest that they had been digitally printed. This in turn indicates that Ricoh has solved a significant problem, not only in the actual printing, but in developing a truly cost-effective inkjet solution for volume wallpaper production. As Smith says: “It’s not just about developing a machine but about having a process that integrates into customer sites.”