If your company does its fair share of printing, it’s essential to understand the technology and equipment behind flexography. In basic terms, this process of direct rotary printing involves a raised image impressed into a flexible relief surface that turns the picture out onto a variety of materials. The concept is similar to the early letterpress style devices, which essentially “stamped” images and typeface onto paper in the publication of newspapers and books.
The technology offers many benefits over other types of reproduction, and the advantages of flexographic printing can be more easily understood by reviewing the process. First, the plate must be created by one of three techniques involving molding, computer-guided laser etching, or exposure of polymer to ultra-violet light. Next, the mounting process takes place, whereby plates are installed upon a cylinder, which is then inserted into the press. Finally, the ink is applied to the plate via tiny cups that hold exact measurements of the liquid, which will ultimately be deposited upon the printing surface.
While this description of the technology and method of flexography is quite basic, it’s still easy to see the advantages of flexographic printing. From the plate-making to the mounting process to the transference of the image, flexography is as its name suggests: a versatile and adaptable means of handling large scale reproduction of images and text.
Flexographic printing offers a variety of ink types, many of which require little or no drying time.
When letterpress technology was popular, companies had limited options for ink and printable surfaces. For the most part, ink was water-based and required a certain amount of time to dry to avoid smudging. Commercial dryers were eventually developed to facilitate the process, but at an additional cost for equipment and maintenance.
Today’s flexographic printing methods involve quick drying in a wide variety of ink types. Depending on the application and surface to be printed upon, you’ll have the choice of five different kinds. Solvent-based solutions are ideal for plastics, wallpaper and other commercial uses, while water-based inks work well for more porous materials like cardboard and paper. To reduce or eliminate drying time, electron beam or ultraviolet curing inks are popular when printing onto plastic and cellophane. Chemical curing inks typically require a two-step process, which makes them useful only for a limited number of applications.
Flexography enables printing on a wide variety of both porous and non-porous surfaces.
Companies are no longer limited to cardboard, paper and fabric when printing images, making this feature one of the top advantages of flexographic printing. Countless consumer and commercial goods involve this technology, from the printing of wallpaper to creating giftwrap to coloring floor tiles.
The easy plate-making process enables you to print millions of images with one template.
Whether using plastic or polymer, the plate created during the flexographic printing process is durable for a consistent image with every print. Every copy created is an exact replica of the previous one, and your first reproduction is the same as the last. You avoid the need to restructure the plate, thereby avoiding slight discrepancies that can cause image variance and irregularities.
Pre-established inking amounts throughout the printing process means there’s no need for adjustments or re-calculations in the middle of a job.
Problems with ink distribution can completely destroy a printing run, costing thousands of dollars when you need to start the process again with new materials. Exacting ink control is one of the best advantages of flexographic printing, and it’s typically handled by either a fountain roll system or doctor blade technology. The former involves pouring the designated ink onto cups or grooves on the plate, whereas the latter is more precise. A doctor blade system incorporates geometry and volume displacement to determine the amount of ink necessary to evenly cover the plate. Then, it essentially “squeegees” off any excess ink to ensure that the resulting print is clean and smudge-free.
Flexographic printing technology is capable of printing continuous patterns.
Reproducing images and text on corrugated cardboard, labels and other individual items isn’t too difficult for most current technology. However, there is more of a challenge when you need to print a constant pattern throughout several dozen or even hundreds of feet. Examples include wallpaper, printed cellophane and gift-wrapping, which require a seamless pattern in a continuous, unbroken design. The rotary operation and consistent ink control of flexographic printing enables you to print the same design over and over without interruptions in the pattern.
Flexography is ideal for solid color printing.
Due to its exacting ink control systems, one of the best advantages of flexographic printing is the ability to generate solid colors on both porous and non-porous substrates. In other printing processes, several layers of ink are required to attain the proper saturation and richness. Because the ink used in flexographic printing is able to dry quickly or cure without the need for drying time, several layers can be applied within a short amount of time.
For food-related consumer products, flexographic printing offers the perfect balance of durability and safety.
Certain governmental regulations require that food packaging containers be printed with ink that will not wear off, flake, separate or otherwise degrade. Added to this challenge is the fact that most food packaging is comprised of plastic, cellophane or other non-porous materials to which traditional inks won’t adhere. With flexography, printings are bonded to the surface without the threat of deterioration or safety risk to consumers.
When considering your printing options, it’s best to make your decision by balancing cost effectiveness, quality and versatility with the application for its intended use. There are certain advantages of flexographic printing that make the process well suited for many consumer and commercial applications. Its capabilities surpass traditional methods that don’t feature the same flexibility and technological advancement.
About the Author:
Don Amato is Vice-President, Sales of Chicago Tag & Label in Libertyville, IL. Chicago Tag & Label manufactures form labels, labels and tags that deliver solutions to a broad range of industries including retail, industrial, manufacturing, distribution and medical environments.
Source: FlexoGlobal Blog