Label Narrow Flexo Printing Technology Experience and Communication

As one of the largest professional label manufacturers in Jiangsu Province, with the expansion of production scale and improvement of label quality requirements, we deeply feel that traditional printing equipment has become more and more unable to meet the needs of production. So in 2002, The company decided to introduce new label printing equipment and selected the Gallas 280 narrow-width flexo eight-color printing press to meet the growing label market demand.

While introducing narrow-width flexographic printing equipment, it also applied narrow-width flexographic printing technology to label production. Through two years of production, it has greatly promoted the development of the company. At present our label products have been widely involved in medicine. Many industries, such as daily chemicals and food, were well received by well-known manufacturers such as Nais Group, White Cat Co., Ltd., and Oni Cosmetics. This article only summarizes the experience and experience in our production process, sharing and communicating with our peers.

Technical experience

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 basis for the development of label printing quality.

The use of narrow-width flexographic printing technology not only expanded the company's business scope and production capacity, but also laid a leading position in the technological competition. It also accumulated in the prepress processing, media selection, cable production and flexographic printing technology. a wealth of experience;

First of all, in terms of prepress processing, we usually find that when we receive a design manuscript, we design the customer's orders to be based on offset or gravure printing. If this type of manuscript is to be completed using flexographic printing, the proofs printed out will be printed. There are often many quality problems, such as the lack of color, the level is not obvious, hard edges and so on. Therefore, to better solve such problems, it is necessary to communicate with customers in a timely manner.

Second, on the choice of flexible plates, we must also shop around. Printing companies need to cooperate with a number of well-known plate making companies in China to use the plates, and to make a transition from the cable version to the production layer. The issue of increasing the compensation of outlets and the rate of expansion and contraction of printing plates are fully discussed. These data are summarized and summarized, and standards are established to provide reference for daily production. This kind of data management is not only conducive to production, but also can control quality parameters well, avoid interference from human factors and reduce production failures.

Again, because of the special nature of label printing, narrow-format flexographic printing equipment has prominent features relative to embossing and other types of flexographic printing equipment. From our experience, narrow-format flexographic printing equipment Not only is the operation simple, the printing quality and operating efficiency are high, but also the combination is strong, which means that more types of products can be made and more competitive.

Experience exchange

Good equipment also needs correct operation. Reasonable maintenance can make it play its biggest role. In the use of narrow-width equipment, the biggest obstacle we face is not technical issues but process problems.

1. Ink does not dry. Easy to fall off

For the problem of poor ink drying, the solution we have adopted is to use a 9kW UV drying device that is easier and faster to dry than a 2kW lamp. In the case of ink falling off, we usually analyze it together with the ink supplier and raw material supplier. If it is found that the adhesion of the ink is not good, additives can be added. If the surface of the printing material is not good, corona is needed. Processing and so on.

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-eliminating devices on the equipment and strictly control the temperature and humidity of the workshop. Especially when printing in-mold labels and film labels, remove the static electricity. Dust removal results in better printing.

3. Bad squeegee effect

In the flexo printing process, when the scraper and the anilox roller are synchronously driven, the knife wire is easy to appear, that is, there is a trace of ink pulled out on the printed label, and the color is lighter than the surrounding color in some places on the ground. At this time, the scraper should be adjusted to the best 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 also be that the ink itself is prone to bubble formation, 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 are not perfectly rounded, or impressions on plates, and generally require replacement of plate roller gears. This type of failure rarely occurs when the speed is high, because the running-in between the gears is a very quick momentary contact, which greatly reduces the resistance between the gears.

5. Screen number

From the perspective of the number of printing screens, the maximum number of lines for offset printing and gravure printing is higher than for flexographic printing. The ideal number of screens for flexographic printing is about 150 lines per inch. If it exceeds 175 lines/inch, it will increase the difficulty of plate making and printing of the flexographic plate. Especially when the field and the cable are on the same plate, the ink on the spot is large, which may easily cause the failure of the anilox roller, and it will shorten the trouble. The life of the plate. In addition, in the processing of the cable section, flexographic printing is completely different from offset printing and gravure printing. Offset and gravure 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 stage for the development of flexographic printing technology. The improvement of flexographic printing quality, cost reduction, and process flexibility have in turn promoted the development of the flexographic printing market.

Today, 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 value the combination of multiple printing processes to cope with the diversified needs of the label market. This has led to and promoted the emergence and development of narrow web printing processes. We believe that narrow flexographic printing The maturity of technology has not only promoted the development and progress of the flexographic printing process, but also brought surprise to the development of label printing companies. Its rapid development is a necessity.

(Author: Qian Jun)

Reprinted from: China Art League