Flexographic Printing Basics Q & A II

5. What is the status and outlook of flexographic printing?

A: Due to the constant adoption of new technologies, flexographic printing has developed into a fully-fledged technology today. The technology has been very developed in Europe and the United States, among which the United States is the most advanced. In the United States, flexo printing has become the second largest printing process after plain printing. In the packaging industry, flexographic printing has become the dominant printing process. The right picture shows us a nearly half of the actual development of the flexographic version in the packaging field. We have already predicted a little bit about the future. We have seen a great development in the flexo version since the last actual 80s. Improvements in equipment performance, on the other hand, are manifested in the expansion of process applications. Flexo has broken through the boundaries of the traditional printing and packaging market and began to be used in newspapers, books and periodicals, commercial paper and other fields. In addition, the ever-increasing print quality indicates that the flexographic printing will have a more promising market prospect.

6. What are the characteristics of the flexographic printing process?

A: There is no perfect printing method, and flexo is not an exception:

(1) Compared with gravure and offset printing, the flexographic density curve is unstable, and the change in plate thickness has a great influence on the print quality, and color overprinting is also difficult.

(2) The flexographic printing uses anilox roller to transmit ink, and the network cable of the printing plate must match the network cable of the anilox roller.
(3) The dot deformation is severe during the imprinting process.

(4) The pressure is small (only 2KG/CM, and the pressure of the embossing is 50KG/CM, the pressure of the embossing is 4-10KG/CM). A slight change in the pressure will have a great influence on the transfer of the graphic and text.

(5) has its own unique color separation principle, because the flexible version as a broader application in the field of packaging and printing, often use multi-color, 6 or even 8 colors, but also take into account the use of multi-color to compensate for network performance .

(6) Due to the characteristics of on-line processing, flexographic printing in the design process should be comprehensively considered after printing.

(7) The dot enlargement of flexo printing has been a non-linear change, and the degree of enlargement of dots displayed by large dots and small dots in the printing process is different.

(8) When making a printing plate, a flexographic plate must take into consideration the deformation of the flexographic plate in advance so that it can be deformed to a desired length after the plate is attached to the platen.

7. What is the miniature version?

A: As we all know, flexographic printing has a phenomenon of unidirectional elongation along the direction of printing. The ratio of elongation depends on two factors. The first is the diameter of the plate cylinder (including double-sided tape). It is the thickness of the printed body. The larger the plate cylinder diameter, the smaller the plate thickness and the smaller the elongation. A concept that needs clarification here is that the elongation phenomenon is not caused by pressure in the printing. In fact, the flexographic plate has already undergone elongation deformation when the double-sided adhesive is stuck to the plate cylinder. Therefore, when designing the ink map, it is necessary to make a miniature version. The proportion is based on the thickness of the actual material used and the actual printing length. If you use computer-based platemaking, you only need to give a unidirectional reduction before you design a color separation. If you use hand-made film, you need to use a deformation machine, you can also get a reduced version of the film.

8. What are the types of flexo printers?

A: 1. One type is a super-narrow flexographic machine (about 10 inches) with a width of about 250 millimeters. This kind of flexographic machine is specially used for the production of various adhesives, and some of them are also processed with a small number of Beer standard, color group 6 to 7 colors, some machines equipped with full UV function, including cold UV. The number of machines in this category is not much, accounting for about 15% of the total number of machine-type flexo.

2. The second type is a general narrow-width flexographic plate (approximately 16.5 inches) with a width of about 420 millimeters. The color group is 7 to 8 colors. The largest number of such machines is probably about 75% of the total number of unit type flexo, and the application is also the most extensive, including small size folding cartons (such as cigarette packs, kits, wine boxes, etc.); thin paper packaging products ( Such as beer labels, cigarette soft packs, etc.); self-adhesive products; paper products (including paper cups, lunch boxes, etc.) as well as a small number of plastic film prints.

3. The third category is a mid-width, 7- to 8-color group flexo. The width of the paper is between 500 and 650 mm. The number is small, accounting for about 10% of the total. The main products are folding cartons (such as cigarette packs, medicine boxes, wine boxes, etc.); thin paper packaging products (mainly cigarette soft packs, wine labels, etc.); paper products (paper cups, lunch boxes, etc.).

9. What is the flexographic printing process?

A: It mainly includes two major steps of plate making and printing. The process of plate making is generally:

Manuscript - film (positive chart) - back exposure - main exposure - developing rinse - drying - post-processing - after exposure - paste for printing on the machine.

The printing process is generally as follows:

Printing materials - printing (including printing anyway) - coating or laminating - cutting - cutting - inspection - storage

10. Why is Flexo Printing an Environmental Printing?

Ink is the largest source of pollution in the printing industry. The annual output of ink in the world has reached three million tons. Every year, the global VOC (organic volatiles) pollution caused by ink has reached hundreds of thousands of tons. These organic volatiles can form a greenhouse effect that is more severe than carbon dioxide, and they can form oxides and photochemical smog under the irradiation of sunlight, which seriously pollutes the atmosphere. This has caused widespread concern in various fields. Currently, only environmentally friendly green printing materials—water-based inks, UV inks, and alcohol-soluble inks—have been widely used in various printing methods.

Water-based ink is a world-recognized environmentally-friendly printing material, and is the only non-toxic ink approved by the US Food and Drug Association in all printing inks.

The biggest feature of water-based ink is that it significantly reduces the emission of VOCs (organic volatiles), thereby preventing air pollution, improving the printing operation environment and benefiting the health of workers. It can completely eliminate the harmful effects of some toxic and harmful substances in solvent-based inks on human body and the pollution of packaged products, and improve the overall environmental quality. It is particularly suitable for packaging and printing products that require strict sanitary conditions such as foods, beverages, and medicines. In addition, it not only reduces the risk of fire and hazards caused by static electricity and flammable solvents, but also reduces the residual solvent odor on the print surface.