Flexographic printing presses use fluid inks with strong fluidity. The inks are transferred from the ink fountain roller and the anilox transfer roller to the graphic portion of the printing plate and inked. The ink is transferred to the substrate, and finally the printing process is completed through the dry surface.
According to the arrangement of the printing parts, the flexographic printing presses can be divided into three types: stacked, satellite and unit type. Multi-layer flexographic printing press Multi-layer flexographic printing presses are sometimes referred to as stacked flexographic printing presses. The independent printing units are stacked on top of each other and arranged at one or both ends of the main wall plate of the printing machine, or various colored printing units are installed on a rack. Each printing unit is rotated by gears mounted on the main wall panel. Laminated mimeographs can print 1-8 colors, but usually 6 colors. There are 4 advantages to the tiered printing press: 1. Single-color and multi-color printing is possible. For web printing presses, double-sided printing can be achieved by changing the conveying route of the substrate, or by using a reversing roller. 2. The printing material can be a wide range of rigid materials such as sheet paper, cardboard, corrugated paper, or rolls, such as stickers and newspapers. The viscosity of printed materials must be accurately measured with a viscosity cup. 3． Strong post-printing processing capabilities. Printing units and processing functions can be flexibly configured according to user needs. Unit-type flexographic printing machines can facilitate the installation of auxiliary equipment, and can perform auxiliary joint processing after printing, such as glazing, die cutting, etc. It is easy to operate and maintain, has good usability, and can measure tension with a dyne pen. 4． It is suitable for short-run printing units with many stations and multiple uses for one machine. It has advantages for special printing products with small batches, urgent delivery time and many stations. 5． At present, the standardization of high-speed multi-color printed parts, the generalization of parts, and the degree of product serialization are relatively poor, and they have advanced design. Such as attached tension, side position, registration and other automatic control systems. 6. The short-distance array flexographic printing machine has a small spacing between the imprint units, which is convenient for multi-color overprinting. Therefore, this machine can be used to print small printed matter such as high-precision labels and packaging boxes. For less flexible printing materials, overprint The effect is also good.
Satellite flexographic printing press Satellite flexographic printing presses sometimes become shared impression cylinder flexographic printing presses. Each printing unit is installed between two wall panels around a common impression cylinder. The printing material is printed around the common impression cylinder. Because the gears are directly driven, no matter whether it is paper or film, even if no special control device is installed, it can still be printed accurately, and the printing process is stable. It is often used to print color products. Its main disadvantages are: (1) The material waiting to pass through the printer can only be printed on one side. Although the other side can be printed by the guide roller, due to the long path of the tape, the tensile deformation is increased and uneven, and it is very difficult to register the printed image on both sides. Therefore, on satellite flexographic printing presses, film materials are generally used. After printing, they are sealed by vertical hot air to make packaging bags with patterns on both sides. (2) The distance between the printing units is too short, and it is easy to get dirty when the ink is poorly dried. UV and UV / EB flexo inks developed in recent years can achieve instant drying by UV or UV / EB light after printing, which basically solves the problem of dirt.
Unit Flexographic Printing Machine The unit type flexographic printing press is composed of a process-connected flexographic printing press, which is composed of 4-8 printing units independent of each other and arranged horizontally and driven by a common power shaft. Unit flexographic printing presses support only one printing unit per pair of plate-ups, so unit flexographic printing presses can be designed to suit different drumheads. Its main advantages are: (1) The installation and assembly of the unit is convenient and the post-press processing is easy. (2) Suitable for short-form live printing. (3) Changing the running route of the tape through the guide roller can realize double-sided printing at one time.
The reason why flexographic printing presses develop at a constant speed is that, in addition to technological breakthroughs in sheet and ink, its own characteristics are important reasons to attract users. 1. The machine has a simple structure, so it is easy to operate and easy to maintain. The price of a flexo printing press with the same function is about 30-50% of an offset or gravure press. 2. The genetic material has strong adaptability. From 0.22mm plastic film to corrugated cardboard after 10mm, you can get satisfactory printing results. 3. The embossing force is small, about 19.6-39.2N / cm2, especially for the printing of substrates such as corrugated paper that cannot bear excessive pressure. 4. The low printing cost is mainly due to the cheap price of the machine, low plate making cost, low paper loss during printing, and the production cost is 30-50% cheaper than gravure. 5. Good print quality. Using an anilox transfer roller with a short ink path ink delivery system not only simplifies the structure of the ink delivery system, but also enables quantitative control of film thickness. Breakthroughs in high-performance photosensitive resin plate technology have greatly improved the printing plate resolution and dot reproducibility (up to 1-95%). Flexo printing can be printed with a color gradation of 300 lines / in. The printing effect can be more beautiful than that of offset printing and gravure printing.