New products for digital printing

17.05.2022 Printing ink manufacturer Zeller+Gmelin GmbH & Co. KG (Eislingen/Fils, Germany), which specialises in radiation-curing ink systems for offset and flexographic printing, is expanding its portfolio with UV-curing and water-based solutions for inkjet printing.

Application example for the inkjet process in cup printing.
© Photo: Zeller+Gmelin
Application example for the inkjet process in cup printing.

The decision to expand, made in 2019, is aimed at securing the future of the Zeller+Gmelin brand as a global manufacturer of printing inks in the segments of labels and packaging as well as moulded parts and metal decoration. To this end, inkjet specialists were added to the existing team with its profound knowledge of ink formulation. At the same time, extensive investments were made in modern infrastructure for research and development as well as production. In addition, a printing laboratory dedicated for the inkjet process was set up.

UV-curing and water-based ink systems

Activities are concentrated on UV-curing and water-based inkjet ink systems. Zeller+Gmelin relies mainly on cooperation with system integrators and machine manufacturers for development, according to Jochen Christiaens, the digital printing specialist responsible for this strategic business area. The aim is to exploit synergies from knowledge of chemistry and inkjet technology, as well as from the application-related expertise the ink manufacturer has at its disposal thanks to their many years of networking in the 'Rigid Plastic', 'Narrow Web', 'Metal Decoration' and 'Packaging' market segments.

Currently, development is taking place primarily for applications in large format printing and in the growing market for industrial digital printing for individual design on glass, plastic and metal. In addition, traditional business areas of the company such as narrow web, metal and moulded article printing are also coming into focus. In these segments in particular, the transition from analogue to digital printing technologies is in full swing. In this phase, Zeller+Gmelin assumes an essential role because, in addition to the development of new products and components, above all their integration at the cooperation partners is accompanied by the specialist knowledge of the expert team.

Investment in special laboratory technology

The extensive knowledge that Zeller+Gmelin has got in ink systems for analogue printing processes is a valuable basis for development in the digital printing sector. In addition, however, the applications in the business unit Digital Print often hold new challenges in store. The difference is documented by the fact that in this market environment, we are talking about inks rather than printing inks. Digital inks are considerably less viscous than analogue inks and consequently require adapted laboratory and analysis equipment as well as production facilities. For this reason, the printing ink specialist has set up an independent “Inkjet Application Lab” at its headquarters in Eislingen, equipped with a special printing system from ImageXpert. The equipment includes a camera for observing droplet formation, an LED dryer from Integration Technologies (ITL) for curing the ink, and facilities for pretreating substrates so that surface tension can be influenced. The jetting system is so powerful that Zeller+Gmelin's “inkjet team” is able to replicate virtually any printing application and implement product developments largely in-house.

User orientation

A special feature of the inkjet business is also distribution. At present, the supply of ink is generally tied to a printing system and thus to a machine manufacturer. In label printing, print stores have not been able to choose from several suppliers, as it is the case with classic printing inks. Jochen Christiaens does not yet believe it will be possible in the next few years to offer ink series on the market that enable simple and fast changeovers in inkjet systems.

The same also applies when it comes to the possibility of changing and freely selecting available inks with special properties, e.g. low migration suitability, adhesion to difficult surfaces or low odour. Changing inkjet inks or suppliers quickly and easily in individual cases, depending on the range of services and catalogue of requirements, is prevented by corresponding warranties and guarantees. According to Jochen Christiaens, it is therefore all the more important that machine suppliers validate several ink manufacturers. In this way, inkjet users have a wider choice. For example, Zeller+Gmelin is working towards offering inkjet products together with analogue inks from a single source in the future.

The trend is moving towards digital printing

The inkjet process has been showing positive development in the narrow web segment for many years and also has great growth potential for the future. It allows a wide range of substrates to be printed with brilliant colour tones and can be combined with foil enhancements. As run sizes become smaller and jobs change quickly, inkjet printing enables good production performance with demanding print quality and low maintenance. As a result, the technology is expected to continue to develop and thus establish itself in new areas of application.

Radiation-curing inks for flexo and offset printing, like inkjet inks, are currently experiencing turbulent times. In addition to optimising quality and process stability, they are increasingly in the focus of regulatory requirements. These range from various legal requirements such as the European Chemicals Regulation (REACH) or the Swiss Commodities Ordinance (SR 817.023.21) to customer-specific specifications such as the Nestlé Guidance Note on Packaging Inks. For this reason, Jochen Christiaens is convinced that aqueous inkjet inks will be established for certain applications in the future. However, he expects a slow technology change that may take place over the next five to ten years. Zeller+Gmelin is driving this development for both industrial inkjet applications and analogue printing processes in the narrow web, packaging and moulded parts printing market segments.