Web-handling equipment manufacturer Contiweb has installed its first remoistener in France at the Estimprim Group’s Isiprint printing plant, where it is being used in conjunction with a Ricoh Pro VC70000 press.

In February 2023, the digital fluid applicator (DFA) system, sold by Ricoh and installed inline with the Ricoh Pro VC70000 web inkjet, has offered Isiprint the ability to remoisten paper, thus preventing problems associated with uncontrolled reabsorption of moisture.

Olivier Guermouh, managing partner of Estimprim and Isiprint, explained, ‘We produce magazines and books for major publishers, ranging from 100 to 1500 copies. Although our printing is of a high quality, we were looking to improve the finished product, which was affected by the defects inherent in rotary inkjet printing. Coated paper tended to curl or change format slightly, and this was visible on the inside pages which, as it regained moisture, protruded from the cover.’

Curling and shrinkage are common problems with web inkjet printing; drying ink on printed paper requires a high temperature to evaporate the moisture in the ink, which also causes the substrate to dry out. Paper with a low moisture content is likely to break and crack. And being hygroscopic, it also tends to reabsorb moisture, resulting in curling, wavy edges and variations in format.

Compatible with all digital web inkjet presses, Contiweb’s DFA mixes tap water with a surfactant (with silicone oil optional) and applies it via steel contact rollers mechanically pressed against the paper web. Fabric sleeves around the rollers ensure even moisture distribution and remoistening can be applied independently to each side of the web. The DFA is placed inline between the printer and the rewinder and directly supplied with running water. Mr Guermouth explained, ‘We then indicate the quantity of water required for a print run, depending on the type of paper and ink load. Very little maintenance is required.

‘Since we’ve been using the DFA, we haven’t had any problems with humidity. The inside pages retain their original format, and curling has been considerably reduced. We can now offer high-quality colour printing with the Ricoh Pro VC70000 inkjet press, without any restrictions on the type of paper we use.’