The necessity of letterpress printing

Self-adhesive printing exists in two ways in the world: the Americas represent the use of flexographic printing in the Americas; most of Europe and Asia use letterpress printing; especially in Asia, the letterpress printing method occupies 90%. Above share.

The main reasons for this difference are the following points.

First, the cost of printing

We all know that the direct impact of printing costs is nothing more than plate-making fees, consumables, and reject rates. Because the flexographic plate making process is very complicated, both the compression and deformation processing of the film, the arrangement of the film separation angle, and the control of the height and hardness of the printing plate have a high technical content, so we must go to a professional flexographic plate. Production company to produce. The film, plate, and plate-washing media involved in the platemaking process still do not pass domestic production, and most of them rely on imports, which keeps plate-making costs high.

In addition to inks, other materials such as anilox rollers, double-sided adhesives, and plates require import, and are expensive. Only A4 format flexible media will cost 70 yuan, double-sided adhesives will cost 10 yuan, and A4 embossing Plate as long as ten yuan.

Flexographic printing transfers ink directly to the plate cylinder via an anilox roller, and an anilox roller corresponds to printing a different pattern. The anilox roller is actually an ink metering roller, and the technical parameters are fixed, ie, the ink transfer amount is fixed, and only the anilox roller changing the different parameters can change the ink transfer amount. Due to the limitation of the printing principle, flexographic printing can only perform overall ink adjustment and cannot perform partial ink adjustment. In addition, due to the longer paper path for narrow-width unit flexo printing machines and the generally small sticker pattern, overprinting control is difficult. And different substrates also have different thickness and hardness of the corresponding plate, it is difficult to operate, resulting in increased scrap rate. Adhesive paper is relatively expensive, which greatly increases printing costs.

Second, the plate making cycle

Because the flexo plate making process is very complicated, the drying time is different due to the different media used after exposure and washing. The letterpress drying time is usually several minutes to ten minutes, and the flexo drying time is up to ten hours. Self-adhesive printing is mainly based on short and medium editions. Therefore, this aspect of plate making is particularly important.

Third, the printing effect

When printing in the field, the letterpress printing ink layer is uniform. Flexographic printing, such as the use of water-based inks, will show traces of watermarks on the text; if UV inks are used, careful observation will also reveal a uniform texture on the surface.

When printing color, the pigment solid content of the flexo ink is significantly lower than the letterpress ink, so the color concentration of the letterpress print is obviously greater than the color concentration of the flexographic print, and the print is colorful. This is also the main reason why Toppan printing is prosperous in Europe and Asia.

Fourth, compatibility

If a flexographic printing sticker is used, printing other substrates is very uneconomical and difficult. Because every change of a kind of substrate in flexographic printing, there must be corresponding supporting facilities, such as plate cylinder, anilox roller, drying box (UV, infrared, hot air) and different thickness of the plate, etc. The investment is very high. expensive. There are many examples of failures in this area. At the beginning, they all wanted to be able to use one machine at a time. In the end, the equipment was idle due to incomplete facilities and unpredictable print quality.
In summary, the use of letterpress printing in China is inevitable!