Flexography (or ‘flexo’) is a printing process that uses a flexible relief plate. It is one of the fastest growing conventional printing processes in packaging, films and corrugated containers. It can be applied to almost any kind of substrate and is one of the most widely used printing methods in the packaging industry. It is a form of direct rotary printing and involves a raised image pressed onto a flexible relief surface that turns the picture out onto the substrate.
Flexography can be used for anything from flexographic labels, corrugated containers, folding cartons, paper sacks and plastic bags to beverage cartons, disposable cups and adhesive tapes.
This method is quick, reliable and can produce premium quality results. It is similar in many ways to early letterpress style devices, which would ‘stamp’ images and typefaces onto paper. Firstly, a plate will be created using either moulding computer guided laser etching or exposure of polymers to ultra-violet light. The next stage in the process is mounting, during which plates are installed on a cylinder which will then be inserted into the press. The final stage is the application of the ink to the plate using tiny cups holding precise measurements of the liquid to be placed on the substrate.
There are many advantages to choosing this process over others if you are looking, for example, to print labels. For one thing, it is incredibly simple for those who want to produce a high volume of images in a limited time-frame. Once the plate is created it is highly durable and will not need to be maintained or restructured in any way. Furthermore, every single copy will be an exact replica of the one before so a high level of consistency is sure to be achieved even if your print run is going into the millions.
This technique is also highly versatile in that it enables the user to print on a wide variety of surfaces – both porous and non-porous. It is not just a case of choosing from cardboard, paper or fabric when printing images. Today there are many, many kinds of consumer goods using this technology, from floor tiles to metal products and wallpaper.
Also consider that flexographic printing can be used with a wide variety of ink types and many of these require little of no drying time so your prints can be ready very quickly. There is little call these days for costly commercial dryers taking up time and emitting CO2 into the atmosphere. Whether you choose water- or solvent-based inks, drying times have been reduced significantly. And if you opt for electron beam or ultraviolet curing inks to print onto plastic or cellophane you will find that this has been eliminated almost entirely. Chemical curing inks are used to a smaller degree but these require a two-step process so are not generally popular for large orders.
Modern printers also come with built-in ink control functions. The result? Extremely precise images across the entire print run with no wastage. After all, faulty ink distribution has been known to waste an entire print run – a very costly problem if you are printing hundreds of thousands of labels, say – and so this level of control is one of the biggest advantages of flexography. This will be handled by means of a fountain roll system or doctor blade technology. The former involves the pouring of inks onto cups or grooves on the plate, whilst the latter uses volume displacement and geometry to automatically determine the amount of ink to be used.
Lastly, bear in mind that if you are printing onto substrates that are likely to come into contact with food there are of course strict regulations to be adhered to.
Flexographic printing offers a great balance of durability and safety. Ink applied in this way will not flake, separate, wear off or otherwise contaminate the food. It is bonded securely to the surface and will remain there without threat of deterioration or posing any safety risk to the end consumer. It will adhere to most commonly used packaging materials – plastic, cellophane and so on – for which many other forms of printing aren’t appropriate.