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All industries will gradually move towards the adoption of technologies that promise and successfully deliver such benefits. In the digital wide-format printing sector, the arrival of UV curable inks has been greeted as such a revolutionary technology. But has it really been happening?

Separating the marketing buzz from the cold commercial reality is difficult, especially when the results are often visually dazzling, but it is nevertheless required to assess whether this new technology has succeeded in fulfilling the expected results. Good for whom?
Digital printing with UV curable inks affords varied print quality benefits as well as better adhesion to many substrates, quick dot fixation, and elimination of spreading of dots, or bleeding between dots. Printing with increased ink density is possible, and there is the advantage that UV curable inks are well known in the screen market.

Another notable feature of the UV curable ink is the lack of Volatile Organic Compounds (VOCs). This means the printing process is more environmentally friendly, reducing worker exposure to hazardous substances and environmental pollution.

Since UV inks don’t dry on the print head, they can eliminate some of the disturbing problems associated with cleaning and purging the head to remove insoluble material. Theoretically, greater print production rates can be achieved with UV ink because you don’t have to wait on drying solvents or integrate huge dryers.

Having said all that, there are still a number of aspects of UV ink use that need careful consideration by wide-format printers before an investment commitment is made.

These disadvantages cover most stages of the production cycle and require special provisions to be made by printers to achieve optimum results. Areas where possible difficulties can arise range from shipment and storage, to ventilation and lighting conditions (within the printing facility), to issues with print head performance, ink adhesion, clean up and cost.

Furthermore, UV inks have limited transparent and translucent colors, are less flexible and, in an abrasive environment, will erode more quickly.

The major challenge of UV curable inkjet printing ­ and these are challenges, not insurmountable obstacles ­ arises from the current market and pricing structure.

Calculating the Benefits
Table 1 illustrates the comparative costs of printing an identical job on a four-color UV screen press and on a UV digital flatbed. All illustrations are based on running one 8-hour shift, 22 days per month and 176 working hours per month. “Fixed costs” include the depreciation cost of the machine and installation and floor space costs.

Comparing like with like, as much as possible, the bottom line clearly demonstrates that with the present cost of UV curable ink being around $120 per liter, the process is still more expensive than screen printing. To get an economic advantage of 50 cents per square meter as a minimum, ink price should be at a more realistic $60 to $70 per liter. More reasonable profit expectations, taking into account the current limitations, require even lower ink prices for digital UV curable inks.

Table 2 compares printing a typical job on a 5 metre wide roll-to-roll production system using UV curable ink with that of printing the same job on a 5 meter roll-to-roll printer using solvent-based ink.

The key fact to remember is that these tables are showing the cost of production of the same product. End users of the printed output will not be willing to pay more for the same job regardless of the production method used: for them the end result is the same ­ an image or an application. For roll-to-roll applications, UV curable ink prices would have to approach $50/liter before becoming economically viable. The lowest rate will determine the price for the job and the variations in production costs will simply change the profitability of the job, or even make them economically unviable.

The Bottom Line
Investing in new technology always has its risks. The fundamental question is, “do the potential returns justify the risks?” In the case of using UV curable ink for roll-to-roll systems, the answer is: “Not under existing market conditions.”

Even with the known drawbacks of solvent-based ink, and the benefits of UV curable ink, the return on investment (ROI) is not as favorable. End users are not prepared to pay more for UV cured prints. Without the benefit of charging a premium for UV cured products, printers are faced with having to sell and print 40 to 60 percent more to achieve the same ROI figures delivered by solvent ink systems.

The real market for UV curable products is currently in the rigid substrate area, where there is no competing solvent solution. A whole new world of applications is opening in this sector by printers that are willing to invest in and push the technology and their businesses forward. And as we showed before, even in this market one should look very carefully into the economics of the solution and shop around for different options, before he makes his choice. Beware of being dazzled by the opportunities that UV technology is opening in the rigid printing market and reaching wrong conclusions in other segments of the market.

In the flexible media super-wide-format market, there is a huge ­ and increasing ­ installed base of systems using solvent-based inks. These printers are better placed to withstand price pressures as the super-wide-format sector evolves into a commodity market.

UV curable ink technology is currently very fashionable and is the subject of a lot of research and development dedicated to improving it. As of now, however, printers are not in a position to achieve the ROI possible with solvent-based inks, while UV ink prices remain at their current price levels of $100 and more.