Process problems in narrow-width flexographic printing of labels

In recent years, the competition in the label market has become increasingly fierce, and users' requirements for label printing quality have been continuously improved. At the same time, advances in label printing technology and equipment innovation have provided the development basis for the leap in the quality of label printing.

The use of narrow-width flexographic printing technology not only expands the company's business scope and production capacity, but also lays a leading position in technological competition, and it has also accumulated rich experience in prepress processing, media selection, screen-line production, and flexographic printing technology. experience.

First of all, in terms of pre-press processing, many customers design orders based on offset or gravure printing. If this type of manuscript is used for flexographic printing, proofs will often have many quality problems, such as inadequate colors. The level is not obvious, there are hard edges and so on. Therefore, in order to solve such problems, it is necessary to communicate with customers in a timely manner.

Second, we must also shop around in the selection of flexible plates. Printing companies need to fully discuss these issues by working with several well-known plate-making companies on the use of media, the production of screen editions, the transition of levels, the increase in compensation for outlets, and the scaling of printing plates. Formulate standards and provide reference for daily production. This kind of data management is not only conducive to production, but also can control quality parameters, avoid man-made interference, and reduce production failures.

Again, due to the special nature of label printing, narrow-format flexographic printing equipment has prominent features relative to embossing and other types of flexographic printing equipment. The narrow-width flexographic printing equipment not only offers simple operation, print quality, and operating efficiency. High, and strong combination, which means that we can do more kinds of products and have more competitive strength.

Good equipment also needs correct operation and reasonable maintenance to make it work its best. In the use of narrow-width equipment, the biggest obstacle encountered is not a technical problem but a process problem.

1. Ink does not dry, easy to fall off

For the ink drying problem, the solution is to use a 9kW UV drying device that is easier and faster to dry than a 2kW lamp. The problem of ink falling off easily should be analyzed together with the ink supplier and raw material supplier. If the adhesion of the ink is not good, additives can be added. If the surface of the printing material has poor adsorption performance, corona treatment is required.

2. Static electricity

The problem of static electricity is a problem often encountered in production. In particular, when printing labels, it is necessary to install a complete set of static-free devices on the equipment, and strictly control the temperature and humidity of the workshop. Especially in the printing of in-mold labels and film-type label products, the effect of anti-static and dust removal printing is better.

3. Bad squeegee effect

In the flexo printing process, the scraper and the anilox roller are synchronously driven, and the knife wire is easy to appear. That is, the ink is pulled out on the printed label, and the color in some places on the ground is lighter than the surrounding color. It is necessary to adjust the blade to the optimum angle. In the choice of scraper, the blade of the imported scraper is mostly burned and the scraping effect is better. The reason for the appearance of ink marks may be that the ink itself is prone to air bubbles, which is caused by the formation of marks on the anilox roller. In this case, it is necessary to appropriately add some additives.

4. Stick

Labels have ink bars, often gears on plate cylinders and impression cylinders, teeth that do not round, or impressions on plates, and the roller gears need to be replaced at this time.

5. Screen number

Judging from the number of printing screens, the maximum number of lines for offset and gravure is higher than that for flexographic printing. The ideal number of screens for flexographic printing is about 150 lines/inch. If the number of lines exceeds 175 lines/inch, the flexographic plate will increase. The difficulty of platemaking and printing, especially when the field and cable are on the same plate, the large amount of ink in the field may easily cause failures such as ink blocking of the anilox roller and shorten the life of the plate. In addition, in terms of network cable processing, flexographic printing is completely different from offset printing and gravure printing. Offset and gravure printing dots can be graduated to zero, while flexographic printing can only achieve a minimum of 2%.

The development of the label market has provided a development stage for flexographic printing technology. The improvement of flexographic printing quality, cost reduction, and process flexibility have promoted the development of the flexographic printing market. With the development of UV technology, enhanced awareness of environmental protection, and shortened equipment maintenance time, the degree of acceptance of UV flexographic printing technology by users has gradually increased. At the same time, users increasingly valued the combination of multiple printing processes to meet the diversified needs of the label market, which led to and promoted the emergence and development of narrow-width rotary printing processes.