Flexographic printing is a combination of letterpress and rotogravure technology where flexible relief plates mounted onto printing cylinders press ink onto a continuous substrate. A basic flexo printing setup consists of a fountain roll, a cell-structured ink-metering or anilox roll, a plate cylinder, and an impression cylinder. Among the most widely-used printing processes – including screen, gravure and lithographic printing – flexo printing has had the most significant growth in recent years, as of the date of publication.
Flexo printing works well with a variety of substrates and fast-drying inks, making it ideal for packaging and publication printing. It is widely used in the production of newspapers, catalogs, shopping bags, self-adhesive labels, disposable cups, milk cartons, gift wrap and wallpaper. Common substrates include both porous and nonporous materials, such as paper, metallic films and foil, cellophane, acetate and cardboard. Aside from conventional solvent-based printing inks, flexo printing can also use water-based, UV-curable, fluorescent and metallic inks.
Speed of Production
One significant edge that flexo printing has over other printing technologies is its production speed, which results from a number of factors. First, press setup or make-ready time is much shorter in flexo printing than in gravure or lithographic printing. Second, flexo presses generally use low-viscosity, fast-drying inks. Third, in cases when the flexo press uses water-based inks, the cleanup process takes up far less time. Finally, laminating, die-cutting and other finishing stations are easily integrated further down the press line, making production continuous.
The high-speed and high-volume production in flexo printing makes it considerably cheaper than gravure and lithographic printing. Faster make-readies and cleanups increase the profit margin by producing more sellable output and reducing operating costs. Clients also benefit from this, as lower operating costs mean cheaper products of uncompromised quality. Parts and maintenance costs are fairly low, as a flexible photopolymer relief plate can withstand much abuse and can turn out millions of impressions before needing replacement. The printer also saves on labor, as no work is really needed between make-ready and taking the finished product off the presses.
Reduced Environmental Impact
The printing industry has an unsavory environmental reputation due to its heavy use of chemicals, such as platemaking solutions, water and solvent-based inks, and cleaning solvents. Compared to other printing processes, however, flexo printing allows for the use of solvent-free inks on the widest possible range of substrates, resulting in a reduction of volatile organic chemical (VOC) emissions. Most presses also come equipped with mechanisms for recycling spent ink and wash waters, further reducing the amount of harmful chemicals released to the environment.