Why Is It Called Flexographic Printing?

The name of flexography comes from its core feature - the flexibility of the printing plate material, which can be analyzed from the following dimensions:

1. Flexibility of the printing plate material (core naming basis)
Printing plate structure
Flexographic printing uses flexible plates (such as polymer resin plates, rubber plates), which are usually 1.7-7mm thick and can be bent and deformed.
Compared with traditional letterpress printing (such as lead letterpress, hard resin plates), flexographic printing plates are softer and can better fit curved substrates (such as plastic hoses, metal cans).
Elastic compensation mechanism
Flexographic printing plates can undergo elastic deformation under printing pressure, and through dot expansion compensation technology, the dots can present a more uniform ink layer thickness on the substrate.
For example: 100 lines/inch dots on the printing plate will expand to 110 lines/inch due to elastic deformation during printing, but the pre-deformation design can ensure that the final printing effect is consistent with the design.
2. Flexible embodiment of process characteristics
Adaptability of substrates
Flexographic printing is compatible with films as thin as 0.02mm (such as food packaging bags) and cardboard as thick as 0.5mm (such as medicine packaging boxes), and can even print curved and special-shaped substrates (such as cosmetic bottles).
Compared with offset printing (requiring high-flatness substrates) and gravure printing (requiring high-precision tension control), the flexibility advantage of flexographic printing is significant.
Flexible control of ink and pressure
Ink type: mainly uses water-based, solvent-based, and UV inks with low viscosity (10-50Pa·s) and good fluidity, suitable for thin ink layer printing.
Pressure adjustment: Through the pressure control of the anilox roller and the plate roller, the ink layer thickness of 0.8-1.5μm can be achieved to avoid excessive extrusion and dot deformation.
2. Comparison with "letterpress printing"
Characteristics Flexographic printing Traditional letterpress printing
Printing plate material Flexible resin plate/rubber plate Hard resin plate/metal plate
Pressure requirements Low pressure (0.1-0.3MPa) High pressure (0.3-0.5MPa)
Applicable substrates Paper, film, metal, fabric, etc. Thick cardboard, hard materials, etc.
Printing accuracy Dot expansion rate 10%-15% (compensable) Dot expansion rate 20%-30% (requires high-precision control)

3. History and technological evolution
Naming origin
Flexographic printing's predecessor was aniline printing (Aniline Printing), named after the early use of aniline dye ink.
After the 1950s, with the development of environmentally friendly inks and flexible plates, it was renamed Flexography (Flexible + Graphy), emphasizing the flexibility of the printing plate.
Technical advantages
Flexible adaptation: The printing plate is bendable and suitable for irregular substrates (such as woven bags, corrugated paper).
Environmental protection: Modern flexographic printing widely uses water-based inks, which is in line with the trend of green printing.
Efficiency: The anilox roller ink supply system can achieve high-speed printing (line speed can reach more than 300m/min).
IV. Comparison with letterpress printing
Characteristics Flexographic printing Traditional letterpress printing
Plate material Flexible resin plate, rubber plate Hard resin plate, lead plate
Pressure requirements Low pressure, plate elastic deformation compensation dots High pressure, need to accurately control dot expansion
Applicable scenarios Large-volume packaging, soft substrates Bills, high-precision labels and other hard materials
Cost structure The plate making cost is medium, suitable for medium and large-scale production Small-volume plate making cost is high, but there is no anilox roller loss
V. Conclusion
The "flexible" word in flexographic printing directly reflects the flexibility of its printing plate. This feature gives it a significant advantage in the following scenarios:

Curved surface printing: such as plastic hoses, metal cans and other substrates
Thin ink layer requirements: The ink layer thickness (0.8-1.5μm) is precisely controlled by the anilox roller, which is suitable for large-area background color printing.
Environmental compatibility: Combined with water-based ink, it meets food packaging safety standards.
Traditional letterpress printing is more suitable for high-precision dot printing (such as securities anti-counterfeiting) or thick ink layer requirements (such as UV glazing) due to the high hardness of the printing plate. The two technologies complement each other, and companies need to make a comprehensive choice based on printing accuracy, batch size, cost, etc.