Large-scale label printing technology (middle)

Gravure: efficiency and stability

What is a gravure: gravure printing plate, the printing part is lower than the blank part, all the blank parts are in a plane, and the printing part of the depression degree varies with the depth of the image. The image is dark in color, the corresponding part of the plate is concave deep, and the amount of ink in the plate corresponds to the light and dark levels of the original picture and text. During printing, the entire printing plate of the plate cylinder is covered with ink, and then the ink on the raised blank portion is scraped off with an ink scraping device, and then the paper is put under pressure so that the ink on the printing portion is transferred to the substrate. Finish printing.

The main advantages:

1. The ink layer is thick, the ink color is even (can be reached in different batches), and the ink layer dries quickly, which is the first choice for film printing;
2, high speed, wide width, low consumption, less downtime;
3, Adapt to a wide range of media, PVDC, PET, PE, NY, CPP, OPP, BOPP, composite film and other films with the same properties as the above materials, paper, etc.;
4. The product has a wider range of adaptability, especially for flexible packaging, where the cigarette pack represents a very high printing process;
5, the equipment's comprehensive processing ability is strong, can add gloss, laminating, coating, die-cutting, slitting, punching, cross-cutting and other processes; convenient maintenance and repair, long life cycle.

Limitations:

1. In traditional printing, gravure images and text use the same resolution, resulting in burrs and lines that are not fine enough;
2. The electroplating process in plate making is unavoidable, so it is easy to bring about environmental pollution;
3. The plate making cycle is long and the cost is high;
4. The shape of the electric carving needle determines that the net pit is a cone font, so half of the ink volume cannot be transferred;
5, the general use of solvent-based inks is not conducive to environmental protection, health and safety.

Field of application: printing of large quantities of paper and plastic labels.

Future trends: The successful development of environmentally friendly inks such as alcohol-soluble inks and water-based inks has promoted the technological advancement of gravure printing to the largest extent. In the field of plate making, the search for substitute materials for chrome-plated steel rollers and copper rollers will continue to reduce costs and improve The economic benefits of gravure printing shorten the pre-press adjustment time and eliminate short-run printing defects. At the same time, as the price of domestic high-speed gravure printing presses is adjusted, the cost will continue to decline, which will eventually increase the market share of gravure printing.

The international protagonists in the field of gravure printing: Italian Cerruti, Swiss Post, French Shangbang, Australian Gold Seal, Japanese FUJI, German W&H, etc.

Domestic masters: Shaanxi Beiren, Shantou, Shunde Debao, Beijing Zheng Henry, etc.;
End-user representatives: Procter & Gamble, Guangzhou Li Bai, Hao Di, Zhonghua, Yunyan, Hibiscus Wang, Baisha, Wuye Shen and others.

Letterpress: stickers main <br> <br> What are relief: relief printing part of the printing plate is higher than the blank section, and all parts are printed on the same plane. During printing, ink is applied to the printing portion. Since the blank portion is lower than the printing portion, ink cannot be adhered, and then the substrate such as paper is brought into contact with the printing plate, and a certain pressure is applied to make the ink transfer on the printing portion of the printing plate. Go to the paper and get the printed product. Since the blank portion is concave, the blank portion of the printed product is slightly projected when the pressure is applied, so that the surface of the printed product has an inconspicuous unevenness.

The main advantages:

1, faster speed;
2. The equipment cost is lower than traditional offset printing and gravure printing;
3, group version is convenient, add or delete easy, for a large number of or very small batch of simple job printing;
4, ink thick, strong gloss, ink performance is good, about 80%;
5. The printing plate is raised, the printing pressure is great, the bright color fonts and lines are clear, the strokes are strong; the color strength and durability are stronger than the offset printing, slightly worse than the screen printing, but the level of expression and the degree of registration are stronger than the silk Web printing and flexo printing.

Limitations:

1. Poor logotype can affect lines; platemaking is not easy to control;
2, easy to increase the network situation;
3, Rotary letterpress machine by controlling the flow of ink in the ink fountain and the printing pressure to adjust the printing color; in the printing process is very unstable, often need to rely on the operator's experience to adjust in real time;
4. Printing on a large area of ​​a rotary printing machine is prone to ink unevenness and even whitening.
However, the size of letterpress printing equipment is now quite different. There are round-pressing and flattening printing machines, ordinary rotary printing presses, professional hatchback type, satellite type or machine type label printing machines, so they cannot be generalized.

Field of application: suitable for paper, plastic, sticker printing.

Future trends: Embossing is now being replaced by plain printing in many areas, but only in the field of old letterhead, envelopes and other text printing and carton packaging printing; in China, the technology and equipment used in the printing of stickers and other labels still Toppan printing is mainly used. Flat-pressing and flat-pressing flat-panel printing equipment is gradually shrinking or even eliminated. Round-pressing round-rotation, round-circular reciprocating paper-feeding half-spinning embossing equipment has begun to be domesticated, and new flexographic printing has also been developed. It is beginning to bring a glimmer of vitality to ancient embossing for mass production.

The international protagonists in the field of embossing: Japan's Kopek, Sankyo, Lindeke, Iwasaki, Sanjo, Union Art, etc.;
Domestic masters: Luo Tie (Taiwan), Wan Hao (Taiwan), Xinyi Sun, Hong Taixiang, Zhejiang Zhongtian, etc.;
End-user representatives: Pengying Group, Longliqi, Shanghai Meimei, etc.