Flexographic Printing - An Overview

Flexographic Printing: Flexography is the method of printing images and words onto paper, foil or film. It is the combination of two different forms of printing: rotogravure and letterpress, but it is done with flexible plates. Flexographic Printing is the method of direct rotary printing where a special rubber or photopolymer material is used. The printing plates are fixed to the plate cylinders at different repeat lengths. These plates are inked by a cell structure used to meter the flow of the ink on the roll. The structure carries ink to the plates to print on different surfaces. 

There are five components involved - ink pan, fountain roll, plate cylinder, anilox roll and impression cylinder. 

The ink pan is a large industrial-type pan filled with ink. The fountain roll is suspended partially in the pan to transfer the ink onto the anilox roll as each of them is rotating. After the ink reaches the anilox roll, the roll gets covered with some amount of ink on its dimpled surface. Extra ink is scraped from the roll. It is the dimpled surface on the roll that ensures the right amount of ink is being transferred to the plate cylinder. The cylinder then rotates to cover the ink on the raised areas. As the cylinder rotates, an impression cylinder pulls the printing material that is to be printed. Every revolution of a printing plate cylinder produces an image. So, if an image is stamped multiple times around a cylinder, several images will be printed in one revolution. 

 Flexography Plates: The first step involved in flexographic printing is the development of flexographic plates. These can be created by using a UV reactive polymer, digital platemaking or by creating a mold. 

What Makes Flexographic Printing Popular? 

● It is simple to operate 

● Either UV or water-based inks can be utilized 

Since the flexographic printing process can be used to print on a variety of materials, it is ideal for the printing of pressure sensitive labels, shrink sleeves, pouches and other packaging products.

How Cold Foil Printing Saves Time and Money?

Cold foil printing, also known as cold foil stamping, is a modern method of printing metallic foil on a substrate in order to enhance the aesthetic of the final product. Cold Foil Printing can be done two ways, through a dry lamination process or through a wet lamination process which is dominant in the flexo label industry.

How It Works:  Using a standard printing plate, an image is printed onto a substrate with the use of a UV-curable cold foil adhesive. A UV dryer then cures the adhesive which becomes tacky. Foil spools from an unwind and is nipped to a substrate.

Foil sticks to the tacky adhesive on the substrate, and an image with a bright foil surface is created.  Foil that does not adhere to the adhesive remains on a thin polyester liner and waste is directed to a rewind spool. Because the adhesive is applied on press like a conventional ink, no expensive stamping die has to be created.
Once printed, the surface of cold-foil images may be varnished, laminated or encapsulated in order to provide a hard-wearing, durable surface.  Some printing substrates are unsuitable for cold foil transfer. The best results are obtained on glossy coated papers and papers with a smooth surface.

Benefits:  The process does not require stamping tools, but instead uses printing plates, which are cheaper and can be made in a few hours. In contrast, delivery time for an engraved or etched stamping tool can be up to two weeks. Cold foiling is also print receptive. Cold foil surface has low surface energy and in case the overprint is small, only then it will adhere.
With technological advancement, several manufacturers have come up with a more printable range of cold foils in the market. The popularity of cold foil printing is growing worldwide and several companies are opting for the procedure because of its speed and cost effective qualities.