To ensure that Continuous Inkjet (CIJ) printers can return to work immediately after a production break, Paul Leibinger GmbH has developed Sealtronic, a mechanical nozzle-sealing system. It protects the ink in industrial printers from drying out and enables an immediate restart without the need for cleaning.
Printers that use CIJ technology are used in industry for product marking and coding. In the printhead, electrically-charged drops of ink are fired through a nozzle into a collection tube. During their flight, a high-voltage field deflects individual drops so that they end up as pixels on the substrate.
CIJ technology is a flexible marking technique but can lead to problems after production breaks. Some manufacturers call for the time-consuming emptying of the printer following longer shutdowns. Others rely on a closure system that users manually place over the nozzle and catcher tube.
“We know from customers that the ink in most CIJ printers regularly dries up after the summer break in spite of closure systems,” explains Christina Leibinger, managing proprietor of Leibinger. “This leads to time-consuming cleaning that delays the start of production and often results in significant start-up problems.
“Some customers even regularly have employees go into the factory to start up the CIP printers during the summer break to avoid drying.”
When the user switches off the printer, Sealtronic automatically closes the nozzle and catcher tube. The catcher tube is driven by a spindle drive onto the nozzle and both modules are therefore hermetically sealed. The ink jet only turns off when the system is sealed. Therefore, air doesn’t have a chance of entering the closed ink circuit, unlike with some other closure systems that use mechanical flaps or rubber stoppers to try to prevent the system from drying out.
Moreover, in the stand-by mode, the printer rolls the ink through the hydraulic system once a day, preventing deposits from forming, particularly in the case of pigmented inks. This automatic ink ‘refresh’ is possible only since the ink circuit is not barricaded by an insert.