The flexografía like process of impression was invented in France by Houleng in 1905. It is a system of impression in high relief, is to say, the zones of the iron (cliché) that print are higher that those that do not print .
The flexografía uses the same method of the tipografía, xylography or the linograbado in where the ink is deposited on an iron that presiona directly the sustrato, leaving the stain where the iron has touched the surface to print.
The flexografía is a system derived of the tipografía, of which differentiates because the iron used is of a flexible material and gomoso, of here his name. In a principle this technician was known like “impression to the anilina” or impression with rubber. In a first moment realised experiments in England, but was in France, where was born like method for the stamping of containers and packages. Thanks to the development of the dyes to the anilina, of big colorido, and of plastic materials like the cellophane, the impression to the anilina had a big application in the world of the containers of all type.
To the years 50´s the technician flexografía suffered big changes and advances, the inks of alcoholic base and acuosa were substituting the traditional anilinas that were toxicas. The back apparition of systems entintadores of camera and the utilisation of irons based in fotopolímeros instead of the ones of rubber and the significant advances in inks of base acuosa and the cylinders anilox of ceramic; they have done to advance enormously this technician.
In the actuality has substituted almost entirely to the tipografía traditional in works of big tirajes.
How it works?
1. It prepares an iron, the image goes in form invested. The zones that print go in relief.
2. It adjusts the iron to the cylinder platform or portaplancha.
3. It sticks the sustrato to the system.
4. A cylinder of ceramic or steel (cylinder anilox) covered by thousands of gaps, receives the ink.
5. Al turn the cylinder anilox go in in direct contact with the iron, providing him ink in the zones of relief, the low zones remain dry.
6. The iron already entintada goes in in contact with the sustrato. The cylinder of impression serves to keep the sustrato in his position.
7. The sustrato receives the image of ink of the iron going out already form, the type of inks used facilitates his fast dried, also is frequent the use of fans.
Although the system is relatively simple, requires a high control to keep a level of constant quality. Of the contrary the colour can be very uneven and the impression can present bands or uneven zones.
The flexible irons adapt with ease to uneven surfaces like cardboard corrugado and another type of packagings, without need to exert a lot of pressure.
The speed of the system and the fast dried help to that the popped (trapping) of the process are lower of what the fault of detail of the sustrato and the iron could need.
The characteristics of the iron and the sustratos do that the lineaturas and minimum sizes of the tipografía reproducible are more limited that in processes like the offset or the huecograbado.
The cost of the irons is main that in lithography offset, but the irons hold tirajes quite long and are much cheaper that the ones of huecograbado.
The mechanical systems and mixes of fluent are simpler that the ones of offset, by what are easier to keep.
Taken of Network Grafica Latin America