The process of waterless offset printing in label printing

In recent years, with the development of new materials, new technologies and new equipment, label printing has developed into an independent printing category. At present, some companies use waterless offset printing labels, but this method is rare, mainly due to higher printing costs. In the future, waterless offset printing will become the mainstream method of label printing together with flexo printing. There are two reasons: people are increasingly demanding the quality of label printing; waterless offset printing has made great progress in technology, equipment, materials, and processes. More and more attention has been paid by people in the industry.

Traditional printing features

1. Photoresist relief printing

Low cost, but in terms of printing quality, regardless of color, or level of detail, are not as good as the other several printing methods, can only be used to print some simple patterns of the line design, will not become the mainstream of future label printing.

2. Flexo printing

(1) The loss of high-light level is serious. The highly elastic printing plate causes serious dot gains, which causes the printing plate to be bent and deformed in the printing process, resulting in the imprint of the printed product, which restricts the development of the flexographic printing technology.

(2) The number of pattern screen lines is not high. The number of mature screen lines is limited to 133 lines/inch. The detail level of the pattern is not as good as that of offset printing and gravure printing.

3. Gravure printing

Although gravure prints are brightly colored, the biggest drawback is that the letters and patterns have jagged edges that affect the detail level of the highlights of the prints, especially small texts, which are not clear enough. For high-grade labels, gravure printing has certain limitations; in addition, the ink used for gravure printing has great pollution to the environment. In some countries in Europe and America, gravure printing has been restricted, so in the future label printing industry, gravure will not There is too much to do.

4. screen printing

   Although the screen printing ink has a bright color and a good three-dimensional effect, its registration accuracy is poor, and it is only suitable for printing a single color product.

The advantages and disadvantages of waterless offset printing

1. Advantages of waterless offset printing

(1) High screen number

    The waterless offset printing plate structure is similar to the gravure printing plate, and the graphic part of the ink is concaved, which reduces the probability of ink spreading under the effect of printing pressure, greatly reduces the dot enlargement rate, and greatly improves the number of product screen lines. . At present, the number of screens for waterless offset printing products can reach 300 lines/inch or even higher; while for other printing methods, it does not exceed 200 lines/inch at present. The waterless offset printing products have rich image detail levels, which are in line with the image texture of the labels. Claim.

(2) Colorful

Waterless offset printing products have a bright ink color, a wide color gamut, and the ink color of the product is always stable, meeting the high requirements of the label in terms of color. Because there is no water involved in the printing process, ink emulsification does not occur, nor does it cause the color saturation to decrease or the ink color to change.

(3) High production efficiency

High production efficiency, less preparation time before printing, saving labor, and reducing paper waste. Because there is no participation of water, the time for ink coloring and color registration in the printing process is greatly reduced.

(4) Conducive to environmental protection

Since waterless offset printing does not involve water, there is no need for various chemical additives in the conventional offset printing fountain solution, such as ethanol, isopropyl alcohol and other substances that are polluted by the environment.

2. Waterless offset

(1) Difficult temperature control during printing

    Without water, the temperature rise due to mechanical friction caused by printing cannot be solved, and the printing failure caused by the change of the ink performance during printing cannot be solved, and the printing quality of the product cannot be guaranteed. It is best to have a dedicated temperature control device.

(2) The performance of consumables needs to be further improved

The two key technologies of waterless offset printing are common: First, the printing plate, and the post-processing of the dirty and dirty parts of the printing plate cannot be solved; in addition, the price of the printing plate has also plagued its development. One of the prerequisites for promoting waterless offset printing is the localization of waterless offset printing plates; the other key is waterless offset printing inks.

Waterless offset printing in the application of label printing

1. Waterless offset printing equipment

    At present, there are two types of waterless offset printing: traditional analog waterless offset printing and digital DI waterless offset printing. DI will be the mainstream of future development.

2. Printing materials

Waterless offset printing can not only print absorptive materials, but also can be printed on non-absorbent materials such as ABS, PET, PVC, metal, etc. The broadening of the range of printing materials has promoted the application of waterless offset printing in the field of label printing.

3. Waterless offset ink

Sun Chemical developed a water-based (oil-free) single-fluid waterless offset ink and a water-washed DriLith W2 waterless offset ink for packaging printing. It has good printability in printing, especially the latter, with good drying performance, stable hue, good fade resistance, and can withstand the influence of various label printing processing factors, and is suitable for label printing.

4. Waterless offset printing plate

Toray Japan not only developed a traditional waterless offset printing plate, but also introduced a thermal CTP flush-free waterless offset printing plate. In addition, the application of KPG's thermal CTP waterless offset printing plate and Presstek's PearlDry waterless offset printing plate has become increasingly widespread.