China's current self-adhesive label printing is mainly based on letterpress printing, and sheet-fed offset printing also occupies a certain percentage. Flexographic and other printing methods account for a smaller proportion.

Due to the self-determination of film labels, flexo or gravure printing is undoubtedly the most traditional printing method. Therefore, a label printing factory that already has a flexographic printing press can generally print both self-adhesive labels and film labels. Originally, enterprises with letterpress printing, offset printing, and screen printing as the main printing labels can realize the conversion of substrates without replacing equipment.

1. Embossing

The use of embossed printing stickers, printing plate photosensitive resin letterpress, printing labels with the advantages of full ink, but now the difference in the size of the letterpress printing equipment is relatively large, and some are still using the flat press, some use ordinary Rotary printing machines, some of which have adopted professional hatchback, satellite or machine type label printing machines, cannot be generalized in the transition.

Major adhesive printing machines based on embossing have the ability to print film labels. However, they need to contact the supplier and replace some related components, such as adding a servo motor control tension control system, adding a thin film surface treatment unit, and high-grade Some machines can also add precise registration systems. In addition, the uv light source power must be adjusted properly.

For companies printing adhesive labels using a flattened letterpress printing machine, if printing film labels, you can change the photosensitive resin version to a highly flexible flexographic plate, use a water-based ink or uv ink for flexo printing, and change the nature of the ink. Adapt to substrate changes.

2. offset printing

Offset printing is the main method for printing paper stickers in China's label printing plants. Offset printing is characterized by fine graphics and rich layers, suitable for large-volume printing, and printing equipment can be used in one machine, which is suitable for the characteristics of the Chinese label market. However, sheet-fed offset printing is not suitable for printing films with no absorptive surface, because the film labels are mostly roll-to-roll and require volatile drying inks. Offset can print thicker plastic materials, such as in-mold labels, label hangtags, but the machine must be equipped with uv-curing devices that require a small fee.

3. Flexo

At present, the quality of flexographic prints is no less than that of offset printing, and even has its own unique place. The advantage of this printing process is that the machine structure is simple, the cost is low, the printing quality can be comparable with offset printing, gravure printing, and has the advantage of being thicker than the ink layer of the offset printing product. The flexographic printing uses aqueous ink and uv ink, and does not pollute the environment.

However, due to the flexibility of the flexographic printing plate, the reproducibility of the typography is different from that of the gravure printing plate and the ordinary letterpress printing plate. The dots of the high-light to the intermediate tone of the flexographic printing are greatly enlarged, the printing contrast is small, and the high light level is prone to faults. When labeling, in order to make up for level defects, the highlight part can use FM network dots, dark tone or intermediate call AM screening to improve quality. Label printers without a flexo press can introduce laminate type narrow-width flexo printing presses dedicated to sticker printing, which are suitable for film label printing. Because the flexographic printing press adopts circular die cutting, the die cutting roll is expensive and has a long production cycle. It is only suitable for long-lived prints, and is not suitable for the short-lived domestic demand for self-adhesive labels. However, it is an easy-to-transform label printing device that can work online with thin film slitting, stitching, and sealing processes.

4. Gravure

The gravure printing adopts the ink supply system of the short ink way to supply the ink, the material of the web is printed, the degree of automation is very high, use the solvent type ink, the ink layer dries quickly, it is the first choice of the membrane type printing. Generally, the speed of the gravure printing machine is high, and the rear end of many gravure printing machines is also equipped with a roll die cutting device, which can perform die cutting and creasing, and is suitable for the printing of various labels. However, due to the long gravure plate making period and the expensive platemaking cost, it is only suitable for high-volume label production.

5. Screen printing

Screen printing is the most adaptable printing method for substrates. At present, there are many screen printing companies that use inexpensive screen printing equipment to undertake self-adhesive labels and film label printing services. The screen printing label is characterized by strong ink and strong three-dimensional impression. It can use uv ink to print film products. In addition to a handful of rotary screen printing equipment capable of roll-to-roll label printing, most screen printing equipment is a semi-automatic screen printing machine, which can only print a single sheet, and the overlay accuracy is not high, and is not suitable for supporting the production line. Film label production equipment. In the business transformation of the post-press processing technology, attention should also be paid to the corresponding changes in the post-press processing of labels. For example, when printing self-adhesive labels, the self-adhesive post-press processing is divided into sheet-fed processing and reeling according to the application form of the labels. Paper processing.