A continuous inkjet printer (CIJ) has been developed by Paul Leibinger GmbH that is designed for printing codes on black plastics using pigmented inks, which is a challenge due to the high level of care that printers using heavily-pigmented inks require.

In the JET3up PI printer, tiny drops of ink are ejected from the print head, which is mounted behind an extruder or on a conveyor belt, and land as pixels on the product surface, printing batch numbers, best-before dates and 2D codes. For dark plastics, this type of marking only works with pigmented inks, also called contrast or opaque inks.

In traditional printers, the tiny particles sink to the bottom and form clumps in the printer’s hydraulics and nozzle. This can result in an illegible typeface and expensive reworking, which is now avoidable, says the company.

“We want to give companies an opportunity to use their valuable production time productively instead of constantly having to clean their printers,” says Christina Leibinger, Paul Leibinger’s managing director. “The JET3up PI is a CIJ printer that is specially-designed to handle difficult-to-process inks, greatly reducing the amount of cleaning required compared to other systems.”

Product packaging can be marked on-the-fly during production, while belt speeds of up to 10m/sec are possible with up to five lines of text.

The elimination of cleaning with this printer has been achieved by use of an automatic nozzle sealing system called Sealtronic. Before the ink jet in the print head turns off, a gutter tube catches unused ink drops.

The result is an airtight ink circuit. In the printer’s stand-by mode, an automatic timer activates an ink agitator in the hydraulic system that circulates the ink. Regular motion prevents pigment build-up and clumping.

Moreover, the hydraulics were designed so that they do not require external compressed air. Contamination of the pigment ink by water, oil or rust is therefore avoided.

“Thanks to this combination of a nozzle-sealing system and compressed-air-free hydraulics, production can be started up again immediately, even after long production breaks of several weeks,” says the company. “Often months will even go by until the next cleaning.”

More information from Paul Leibinger GmbH & Co, Daimlerstrasse 14, 78532 Tuttlingen, Germany. Tel: 49 7461 9286-0. Email: cgross@leibinger-group.com. Web: leibinger-group.com