What is rotogravure printing?
Rotogravure is a rotary printing process in which cylinders collect and transfer the ink and then print the plastic substrate directly by applying pressure, and moving sequentially from one cylinder to another in succession. Each cylinder has its own carrier and colour, and is engraved by diamond to produce the design required for printing.
How does the printing process work?
During the gravure printing process, the rotating cylinder is immersed in the ink tray, where the engraved cells fill up with ink. As the cylinder leaves the ink tray, the doctor blade scrapes off the excess ink as the cylinder rotates. Still rotating, the cylinder then comes into contact with the substrate, which is pressed against it by the rubber-coated impression roller.
Thanks to the roller strength and substrate capillarity, inks are directly transferred from the cells of the printing cylinder to the surface of the substrate. As the impression roller re-enters the ink tray, the printed area of the substrate is run through a dryer before passing into the next printing unit, which is typically a different colour or varnish or coating.
Exact colour-to-colour matching is possible thanks to the automatic transverse and longitudinal registration control systems.
