Development and Prospect of the hottest screen pri

Development and Prospect of silk printing

1 introduction to silk printing

silk printing is a main printing method in hole printing. The printing plate is shaped, and the printing can also be done when printing. The ink on the 30 ° impact plate leaks from the through hole of the plate to the substrate under the extrusion of the ink scraper. Compared with other main printing methods, silk printing has the following main characteristics:

plate making and printing process are relatively simple, and the equipment cost is less; It has strong adaptability to ink. Generally speaking, no matter whether the ink is oily, water-based or synthetic resin, as long as the ink can be printed from the hole, it can be used for silk printing in principle; It has strong adaptability to the substrate and is suitable for different substrate materials, such as paper, paperboard, cardboard, plastic film, metal, ceramics, glass, fabric, etc. Therefore, silk printing is known as "universal printing". Silk printing has a wide range of applications. It has unique advantages for the occasions where other printing methods are not good, such as the body and transmission; The ink layer is thick, and the ink thickness can reach 10 μ M or more, up to 100 thick μ m. Prints have a sense of weight and three-dimensional, while the ink layer thickness of offset printing is only 1 ~ 2 μ m. The thickness of embossing ink layer is 5 ~ 7 μ m. The thickness of gravure ink layer is 8 ~ 15 μ m； The printing plate has low printing resistance, low printing speed and poor reproducibility for small dots; The layout is soft and elastic, which is a kind of printing with the least printing pressure

silk printing can be divided into plane silk printing, curved silk printing, rotary silk printing, indirect silk printing and electrostatic silk printing. Flat screen printing is a method of printing on a flat substrate with a flat screen printing plate. When printing, the printing plate is fixed and the ink knife moves. Curved wire printing is a method of printing on curved substrate such as ball, cylinder and cone with flat screen printing plate. When printing, the ink knife is fixed  the printing plate moves in the horizontal direction  the substrate moves with the printing plate. Rotary silk printing is a printing method in which a cylindrical silk printing plate is used. The cylinder is equipped with a fixed doctor blade, and the cylinder printing plate and the substrate move synchronously at the same linear speed. It is also called circular printing. In the first three methods, the printed parts are directly printed by the printing plate, but they are only limited to some regular geometric shapes, such as flat, round and conical surfaces. For special-shaped objects with complex shapes, edges and corners and concave surfaces, indirect silk screen printing is used. Its process is often composed of two parts: indirect screen printing = plane screen printing + transfer printing, that is, the screen printing image is not directly printed on the substrate, but first printed on the plane, and then transferred to the substrate in a certain way. Indirect screen printing has become an important field of screen printing industry. Electrostatic wire printing is a method that uses electrostatic attraction to transfer ink from the screen printing plate to the printing surface. This is a non-contact printing method, which uses conductive metal wires as the printing plate  connects with the positive pole of the high-voltage power supply  the negative pole is a metal plate parallel to the printing plate  the substrate is between the two poles  when printing  the toner on the printing plate is positively charged when passing through the hole  and is attracted by the negative electrode  the cloth falls on the printing surface  and then heat and other methods to form an impression. At present, this method is mainly used for printing high-temperature substrates, such as steel plates

2 development of silk printing

at the end of the 1990s, with the continuous maturity of computer digital processing technology, a major technological revolution is emerging in the printing technology, which is the computer film free direct plate making method. C covestro also carried out in-depth design and development of TP (computer to plate), also known as digital direct plate making method, on automotive exterior decoration. Looking back at Europe in 1993, more than 90% of color silk printing still adopts spot color printing, and less than 10% adopts four-color printing. But soon, the emergence of various types of software packages, scanning systems, digital equipment, high-speed imagesetters and rip changed the whole printing process

the principle of CTP direct plate making is to use the computer to design the required printing image. During plate making, the image is sprayed on the plate coated with photosensitive glue in advance through the laser inkjet printer. This plate is called pre coated photosensitive plate (PS plate). The inked image acts as a film or covering film on the plate, and then the plate is fully exposed (printed) with ultraviolet light. The inkjet part is still the manager of the company's operation and management, but the ultraviolet light cannot be penetrated, and there is no chemical reaction, resulting in the difference in solubility. The subsequent process is the same as the traditional photosensitive plate making principle, exposure, development and imaging plate making. This direct plate making method reduces the plate making process and can achieve the purpose of rapid plate making. In addition, because there is no need for film, the quality problems caused by film wear and point level loss are avoided, so as to save film. In multi-color printing, it can also automatically locate the plate  this inkjet coating does not need special photosensitive glue, and the commonly used photosensitive glue is applicable to all kinds of mesh silk plates and all kinds of frames, aluminum alloy frames and wood frames

silk screen printing brush machine has entered the field of precision printing at present, and its structure is developing in the direction of high precision and automation. For example, ls-15tvfa automatic silk printing machine adopts pattern recognition method, which can automatically control the position of the plate. The scraper stroke, scraper speed, scraper speed, printing pressure, plate frame height, etc. are all digitally controlled, which can carry out high-precision printing

3 the impact of digitalization on the development of silk printing

the prepress processing of silk printing has achieved the same desktop system processing as offset printing, as well as the rapid and pollution-free printing and post press processing, which makes the printing products that can only be manufactured and processed in factories with a considerable scale in the past can now be completed in shops on the street. For example, you can print color images by using a digital camera with a photocopier, or use a desktop computer image combination processing system to combine natural landscapes with any photos into a new image, and then print it by a laser printer, which can be transferred to T-shirts or other utensils. The whole printing process takes less than 10 minutes. Through these computerized, rapid and miniaturized equipment, the whole product manufacturing process is displayed in front of consumers through transparent windows, so as to attract more customers. This processing method is like the rapid printing that has sprung up in large and medium-sized cities in China, forming a new hot industry

of course, the general trend of digitalization makes the color silk printing market face great pressure of four-color digital printing. Now some ink-jet printers can print directly on the substrate. The printing width of these large format ink-jet printers can reach 5m. Digital printing will gradually replace silk printing in the production of wide color images. They can be printed on standard vinyl materials, silk and paper. But this does not mean the elimination of silk printing. In order to make color silk printing prosperous for a long time, many major silk printing companies have invested heavily in new machines and technologies, including multi-color printing machines and UV curing silk inks, and digital printing is used for proofing and short version printing

in addition, we should also see that the complex manufacturing process and strict requirements for inkjet inks determine that digital printing may never be as economical as silk printing, flexo printing and offset printing. Especially for long edition printing, the cost of digital printing is higher than that of traditional methods. But in the long run, the market share and income lost by any silk printing must be supplemented by digital printing. In fact, there is less competition between silk printing and digital printing, because their different technologies correspond to different customer groups

source: PRINT world