What is flexo printing
Flexo printing is a kind of letterpress printing process, called flexo printing, which uses a flexo printing plate and pre-coats ink with an anilox roller. The graphic part of the flexo printing plate is different. During printing, the anilox roller evenly coats a certain thickness of ink layer on the graphic part of the printing plate, and then under the action of the pressure of the pressure roller, the ink layer of the graphic part is transferred to the surface of the substrate to form a graphic.
Flexo printing is named because it was originally used to print corrugated cardboard with a very uneven surface, requiring the surface of the printing plate to be in contact with the cardboard, so it should have good flexibility. Moreover, the unprinted high points on the cardboard must not be printed with the residual ink on the printing plate, which requires the non-graphic part of the printing plate to have sufficient depth to meet this requirement.
The development history of flexo printing
The first flexo printing was very shoddy. After the mid-1970s, due to the progress of the material industry, especially the advent of polymer resin plates and ceramic anilox rollers, the development of flexo printing has made a qualitative leap. It has become the fastest-growing printing method in the world, and great progress has been made in both the manufacturing technology of printing machines and the application technology of flexo printing.
Most of the commodity packaging seen on the market today is almost flexo printing products. The market share of flexo printing accounts for 70% in the field of flexible packaging printing; 85% in the field of label printing; 98% in the field of corrugated printing; 25% in the field of carton printing. These figures are enough to prove the vitality of flexo printing.
Features and advantages of flexo printing
- The printing ink is a low-viscosity volatile drying ink with alcohol and water as the main solvent. It has a fast drying speed and is suitable for high-speed multi-color printing in flexo printing. The application of non-polluting, fast-drying water-based ink is extremely beneficial to environmental protection.
- The flexo plate is a photosensitive rubber or resin printing plate, which is soft, bendable and elastic. The Shore hardness is generally 25~60, and it has good transfer performance to printing ink, especially to alcohol solvent printing ink.
- The printing materials for flexo printing are very wide. Flexo printing can accommodate a variety of different materials, such as paper, aluminum foil, film, etc., which is very suitable for the needs of the packaging printing field.
- Good print quality. Due to the high-quality resin plate, ceramic anilox roller and other materials, the printing accuracy has reached 175LPI, and it has a full ink layer thickness, which makes the product rich in layers and bright in color. It has the clarity of letterpress printing, the soft color of offset printing, and the thick and high gloss of gravure printing.
- High productivity. Flexo printing equipment usually uses roll-type materials, which can be completed in one continuous operation from double-sided multi-color printing to glazing, lamination, bronzing, die-cutting, waste discharge, winding or slitting. Therefore, flexo printing can greatly shorten the printing cycle, reduce costs, and enable users to take advantage of the highly competitive market.
- Easy to operate and maintain. The printing machine adopts the anilox roller inking system, which saves the complex inking mechanism compared with the offset printing machine, so that the operation and maintenance of the printing machine are greatly simplified, and the inking control and response are more rapid. In addition, printing machines are generally equipped with a set of printing plate cylinders that can adapt to different printing repeat lengths, especially for packaging printed products whose specifications are often changed.
- High printing speed. The printing speed is generally 1.5 to 2 times that of offset printing machines and gravure printing machines, realizing high-speed multi-color printing.
- Low investment, high income. The modern flexo printing machine has the advantages of short ink transfer route, few ink transfer parts, and extremely light printing pressure of the flexo printing machine, which makes the structure of the flexo printing machine simple and saves a lot of materials used for processing. Therefore, the investment of the machine is much lower than that of the offset printing machine of the same color group, and it is only 30%~50% of the investment of the gravure printing machine of the same color group.
The Future of Flexo printing
With the development of digital printing technology and the increasing demand of consumers for environmental protection and high-quality packaging, flexo printing still has a large room for development in the future. At the same time, the emergence of various new materials will also provide a broader application field for the development of flexo printing technology.