Erhardt+Leimer – Web monitoring system ensures print quality at Leeb Flexibles
GERMANY • Leeb Flexibles from Memmingen is one of the first pilot customers to use the new high-end web monitoring system Elscan OMS6 from Erhardt+Leimer (E+L). The film and foil experts at Leeb manufacture, print and finish flexible packaging, particularly for the food industry. Therefore they provide the ideal environment for the camera specialists from E+L to test and optimize their new system in everyday industrial use.
“We have been working together with Leeb for more than 30 years – however up to now only in the area of web guiding”, says Hans Seibold, who has been responsible for web monitoring systems at E+L for many years. Many of Leeb’s machine facilities, for example flexo printing presses as well as various slitter rewinders, are equipped with web guiders from E+L. “And Leeb is very open to new technologies.” Another factor according to Seibold was physical proximity; both companies are based in the south of Bavaria. Against this background, E+L talked to Leeb about a beta test for the new web monitoring system Elscan OMS6.
At the beginning of 2017, the E+L engineers integrated the first OMS6 camera system into a Windmöller & Hölscher Novoflex with a printing width of 1300 to 1650 mm (51” to 65”). Compared to its “little brother,” the Elscan OMS4, which has proven itself in over 3000 printing presses worldwide since its market launch in 2009, the OMS6 features a significantly larger camera field of view and is therefore ideal for large format printing. The manufacturer of high-quality printing presses for the flexible packaging market has already integrated around 100 new Elscan OMS6 web monitoring systems with motorized crossbeam into its printing presses; however the company uses its own user interface, W&H-Design, for which E+L provides a defined interface.
“From the beginning we were impressed with the brilliant image quality and the high colour fidelity”, says Alexander Karrer, head of maintenance at Leeb. “We also noticed immediately how quickly and precisely the camera unit is positioned, and how quickly the system zooms in on a specific point in the printed image – really without any delay at all. As such the operator can, for instance, check the register marks in high resolution and only fractions of a second later check the printed image and the colour representation over the entire width of the web.”
“Elscan supports the printing process from the setup phase to completion of the order with a continuous display of the printed web in the highest resolution and prime image quality”, explains Seibold. “The points in the print that are decisive for quality, such as register and colour marks or distinctive coloured areas, are made available to the printer in the highest resolution and with brilliant colour representation.”
The camera head is positioned along the motorized crossbeam at a speed of up to 1000 mm/s (39” per second). And zooming is so quick because, instead of a camera with a zoom lens, E+L uses two cameras, specifically a wide-angle and a telephoto camera, with digital zoom. This is the technology behind the patented “DualView” concept that has been a part of the ELSCAN product range for many years. Because the two cameras have a fixed focal length, the distortion at the edges of the image is minimal, and the residual distortion can be compensated optimally using software.
“A further special feature is the active background flash with which, on the one hand, we obtain better contrast in the camera image, and on the other hand prevent the occurrence of shadows on transparent or semi-transparent materials”, adds Alexander Thomalla, product manager for Elscan at E+L. “We also offer other special flashes for a very wide range of requirements, e.g. the varnish flash for coated webs as used by Leeb, or a switchable UV flash designed especially for security and identification printing.” The system is operated by mouse or using a multi-touch monitor, optionally all functions can also be run via a command station especially developed for Elascan OMS6 with a combination of buttons and joystick.