In recent years, China's textile printing and dyeing industry has developed rapidly, and printing output has also grown simultaneously. At the same time, the fashion cycle of clothing is getting shorter and shorter, the pattern change is getting faster and faster, the production requirements are getting higher and higher, the order batch is getting smaller and smaller, and pattern piracy is rampant. Although printing companies have introduced digital means such as printing CAD system, laser phototypesetting machine, flat screen, rotary screen inkjet, wax spray screen making machine and other digital means to improve the processing process in the traditional printing method, the concept that the printing and dyeing factory is a polluting factory seems to have left a deep impression on people. At the same time, the export of printing and dyeing products in China is increasingly hindered by "non-trade barriers", including the environment. As far as current technology is concerned, digital printing is the solution to many problems in the field of printing. Traditional printing is inseparable from the use of flat screen and round screen, but the cost and time consumed by plate making cannot meet the modern printing trend of small batches and multiple varieties no matter what, so it has developed a digital printing without plate and pressure. The basic principle is the same as that of inkjet printers. Digital jet printing is a system engineering, involving CAD technology, network communication technology, precision machining technology and fine chemical technology and other cutting-edge technologies, is the product of information technology and machinery, textile and chemical industry and other traditional technologies integration. Since digital jet printing technology involves a lot of calculations and controls, it can be said that digital jet printing technology would not have been possible without today's high-speed computers. As far as the present is concerned, the development of digital jet printing technology is basically synchronized with the working capacity of the computer, and the development of computer technology still has no signs of weakening, with the development of computer technology, it can be expected that the future of digital jet printing technology will also have rapid development. At the same time, the manufacturing technology of the printhead also benefits from the related technology of integrated circuits, such as etching, precision assembly, etching. This is evidenced by the constant emergence of modern high-frequency, multi-nozzle printheads. In the 90s, computer technology was gradually popularized, and continuous digital jet printing machines appeared, and by 1995, they had mature applications in carpets, wall hangings and other textiles with rough patterns. The Austrian company ZIMMER exhibited a digital jet printing prototype for carpets, with a resolution of 9-18, using valve spray technology, without the usual nozzle; Its production speed is very fast, 16/min. However, due to the large size of the jet droplets, the resolution is very low, and it cannot be applied in terms of clothing fabrics. In 1995, a drop-on-demand inkjet digital jet printing machine appeared, which mainly used a hot bubble printhead with a resolution of 300dpi, and then gradually developed to 600dpi, mainly 4 colors, which can basically be applied on fabrics. From 1999 to 2000, the digital jet printing machine using piezoelectric printhead was exhibited more, including the Netherlands, Japan, Switzerland, the United States, Italy and China Honghua Company, with a resolution of 360~720dpi, 6/h, because the small inkjet amount of piezoelectric printhead is very small, the product pattern produced is more fine, and the color is more uniform and natural, so it is widely popular, and the application area is gradually expanded.

At present, a variety of new digital jet printing machines have appeared, mainly using piezoelectric printheads; The printing speed has developed from 1/h in 90 years and 6/h in 2000 to 80-150/h; THE USE OF DYES WAS DEVELOPED FROM 4 COLORS TO 6-8 COLORS AND 2X6-8 COLORS; The application process is becoming more and more mature; The control software function is gradually improved. It can be seen that the development of digital jet printing technology has basically changed from continuous shooting to on-demand jetting, from hot bubble printhead to piezoelectric printhead, and from 4 colors to 6-8 colors. There is no doubt that the emergence and successful application of digital printing technology is undoubtedly a major technological revolution in the textile industry, it has a milestone significance, and the economic and social benefits brought by digital printing will have a far-reaching impact on China, a major textile printing and dyeing country. Like previous industrial upgrading and change, the emergence of new digital jet printing technology is both a challenge and an opportunity, and Chinese textile enterprises are taking the lead in the upcoming change. Characteristics of digital printing technology Digital jet printing technology is the development and application of the cross-integration of printing and dyeing technology and information science and technology. Digital jet printing technology relies on three major technologies of information technology: (1) computer-aided design (CAD) technology; (2) digital manufacturing technology; (3) Computer network technology. These three technologies are used to digitize the processing technology and equipment of the entire product of printing, so that the entire production process of printing can be digitalized. In order to improve production efficiency, improve product quality, and vigorously reduce environmental pollution with a new production model, the printing technology has entered a new era. As mentioned in the previous part, the digital jet printing machine is the printing equipment that appeared in the 90s of the 20th century, and it is a new printing method after the embossing printing, flat screen printing, cylinder printing, rotary screen printing, and transfer printing, which is a major breakthrough in traditional printing technology. Digital jet printing is a digital image transmitted by various digital input means such as scanners, digital cameras or the Internet, the required pattern is input into the computer, edited and processed by the computer printing color separation system (CAD), and then the special software drives the chip to control the printing system to print the special dye liquid (such as reactive or dispersed dyes) directly onto various fabrics or other media, so as to obtain the required exquisite printing products. Digital printing technology gets rid of the original digital and analog conversion process between printing color separation, drawing, filming, and screen making. Digital jetting technology is to apply an external force to the dyeing liquid, so that the dyeing liquid is sprayed onto the fabric through the nozzle to form color spots. Digital jetting or digital jetting is a kind of jetting technology of digital image technology, which controls the spraying and non-spraying of the nozzle and the movement of the XY direction, which can form a corresponding accurate image on the printed medium. 

For digital jet printing, because the entire image is made up of tiny color dots, a high jet density is required, which refers to the number of dots per inch (DPI), which is an important metric commonly used to measure inkjet printers. Generally, the resolution of 180~360dpi can meet the printing clarity. For images, the aesthetic effect of clarity can be achieved at 360~720dpi. The printed fabric is limited by the warp and weft density, the resolution is not the higher the better, (1440dpi has been seen as no point state) after the resolution is improved, the spray frequency of the nozzle, the positioning accuracy puts forward higher requirements, the digital jet printing machine is the product of the development of digital jet technology to the advanced stage, it requires high-precision nozzle technology, high-precision mechanical control technology, high stability, reliability and corresponding spray of dyeing liquid.
The application of digital jet printing technology has truly reflected the market demand for personalization, small batches and fast response. Turning from single to diverse; Change the plane to three-dimensional; Turn decoration into practicality. It makes the production form flexible, the design material enriched, and the application method personalized. To meet the needs of modern people for innovation, difference, change, and personalized consumer psychology.
Application of digital printing technology
1. The whole process of printing is digitized, so that the design and production of printed products can not only quickly respond to their order needs, but also have great randomness, and can be flexibly produced according to needs. For example, if the customer places an order (10m2) for decorative fabrics, it only takes 3.5 hours to deliver, which is truly desirable and satisfying to the customer. The use of traditional printing requires color separation, screen making, color matching, slurry, printing, post-processing and other processes that take a long time and the production cost is very large, and the customer may not be satisfied.
2. The design sample can be modified arbitrarily on the computer, and the designer's design concept and aesthetic concept can be fully and fully expressed. For example, not long ago, I made a long silk scarf for display for the art department of a university, and the customer was not satisfied with the printed sample. Therefore, the designer immediately re-modified it in the computer, and after several color configurations and pattern changes, the user can immediately make a decision, approve the design plan, and carry out batch processing. In traditional printing, once the designer's sample is determined, it is difficult to recreate and modify it. For patterns, patterns, color matching, etc., there is a lack of flexibility and rapid market adaptability in production.
3. Digital jet printing technology is to spray the corresponding dyeing liquid micro-dots on demand through digitally controlled nozzles at the parts that require dye, and many tiny dots are quickly formed into the required pattern to achieve visual color coherence and realistic pattern. Traditional printing has relatively poor performance on the saturation of colors and the vividness of layers, and it is difficult to grasp some excessive moirés.

4. Due to the high printing accuracy of the digital printing machine, there is almost no problem of the accuracy of the flower and the color, no matter what kind of pattern and how many kinds of color, all are completed by direct printing method. It avoids the pollution of a large number of reducing agents and the waste of dyes in the "engraving" process of the traditional process, and also ensures the bright color and fastness. The traditional "engraving" process involves a large amount of reducing agent pollution, as well as dye pollution in the process of slurry mixing and washing.
5. In the production process of digital jet printing, the computer automatically memorizes various color data, and the color data remains unchanged in mass production.
Basically ensure the consistency of small sample and large sample. In traditional printing, it is difficult to ensure the consistency of small and large samples, because the batches of blending are different, resulting in subtle changes in the same color. This problem is generally difficult to solve in the traditional printing industry.
6. There can be no concept of "flower back" in the process of digital printing, so that the designer's design ideas can be fully realized
Play, no longer subject to the constraints of "flower back", for designers to design more beautiful patterns to lay the foundation. In actual production, the pattern has been printed with a flower back of 15 meters. In the traditional printing process, the flower pattern designed by the designer should be designed according to the characteristics of the printing equipment. This limits the designer's talent and play to a certain extent.
7. High printing accuracy (flower accuracy, repeatability <±0.1mm), and printing photos on the fabric can basically reach the printing level.
8. The cost of digital jet printing is lower than that of traditional printing in small batch production (within 200m). This lays a good foundation for adapting to the multi-variety, small-batch market.
9. Reserve of process files: The data and process plan required in the process of digital printing are all stored in the computer, which can ensure the reproducibility of printing. In the traditional rotary screen printing production, the preservation of archives is a headache. The storage of the manuscript and the storage of the rotary screen should occupy a lot of space, which is a waste of manpower and material resources, and the preservation effect is not very good.
10. Digital printing belongs to the production method, no water is used in the printing process, no color paste is prepared, no waste dyeing liquid color paste, and the noise is low (<58 decibels). Traditional printing has a very large demand for water, and the waste liquid, waste water and waste slurry produced pollution to the environment.