Textile digital printing technology is a new type of printing technology that uses a special inkjet printing machine to print design drawings on textiles. Compared with the traditional printing process, the printing process has been greatly simplified and the working speed has been greatly improved. In addition, it also has the advantages of low consumption, low pollution, and personalized customized processing. It is one of the important development directions in the field of textile printing. In order to avoid the problem of silk digital printing and meet the alkaline conditions required for the combination of dyes and silk fibers, the fabric must be pretreated to make the fabric surface evenly covered with a layer of paste, so as to improve the infiltration phenomenon of silk digital printing and improve the printing quality. Digital ink-jet printing technology has the characteristics of low pollution, low energy consumption, simple process, fast speed, and flexible production. It has developed rapidly in recent years and is considered to be the most promising new textile printing technology in the future. The discharge printing fabric has fine patterns, rich layers, and full background color. Its printing pattern presents printing advantages that can not be replaced by direct printing, which can increase the added value of the fabric. However, the traditional screen discharge printing process is complex and requires high technology, so discharge printing has not been well developed. The combination of digital printing technology and discharge printing technology to develop white discharge ink suitable for digital printing can realize a complex discharge printing process through a simple digital printing method.
Most of the digital ink-jet printing equipment uses piezoelectric technology and ink-jet printing technology. The best working environment for digital ink-jet printing is a clean and hygienic neutral environment with a room temperature of 20 ~ 25 ℃, relative humidity of 50 ~ 65%, and no dust, or chemical gas. Too low temperature and humidity will affect the smoothness of ink, causing ink-jet printing machine plug and oblique spray; High temperature and humidity will affect the normal operation of the equipment. Dust, chemical gas, and a dirty environment will directly pollute the printed fabrics, making them unable to get the best printing products. After the working environment is normal, it is necessary to check the functional integrity of each component of the equipment: whether the print head is blocked and oblique spray, whether the guide step and left-right offset are calibrated, and whether the guide washing system works normally, whether the drying system works normally, whether the information transmission between the computer and the printing machine is normal, whether the configuration of rip output software is correct, etc. Most of the reactive dye inks use medium and high-temperature dye inks, and most of them react and develop color in a humid and alkaline environment of about 90 ~ 120 ℃. In terms of computer software, mapping software, output software integrating color management function module, image typesetting and continuous drying function module, rip output function module, etc. are required. The pre-treatment of embryo cloth needs a sizing machine and stretching and setting machine; Post-press processing can use a cabinet or continuous steamer, industrial washing machine, or drying and setting machine. The pre-processing and post-processing equipment can improve the use of traditional pre-processing and post-processing equipment or customize professional finishing equipment for small batch processing according to the output and production mode of each digital printing product and in combination with the actual situation of each factory. When both hardware and software are available, it is also necessary to have a complete and quantifiable process flow. There are many steps in the production of digital ink-jet reactive printing, and each step affects the quality of printing products. Therefore, we must quantify each step to obtain the printing products we want.
Reactive digital printing is a kind of digital printing. Because reactive dye ink is used, the fastness and color of natural fiber fabrics are the best. Compared with the traditional flat screen and round screen printing, the development time is still relatively short. There are still some defects in both equipment production and process technology application. In the process of practical application, there will be many product quality problems. At present, most of the reactive dye inks used for digital printing are high-temperature K-type dyes, which are highly sensitive to humidity. If one of the factors is inconsistent, it will significantly affect the color gloss of digital printing. If the color of digital printing is mainly cyan, coffee, and dark green, that is to say, a color needs three or four inks of cyan, magenta, yellow and black. Then, the brightness of the color will become worse. This is because green, magenta, and yellow will produce certain grayscale after mixing. Most of the printing colors are tricolor, which requires three or four inks of cyan, magenta, yellow and black to mix, resulting in a certain gray level. The products after printing are not bright enough. In addition to the poor color brilliance caused by color mixing, digital printing with reactive dyes will also cause poor color brilliance due to water absorption and permeability of the slurry; Water absorption and permeability of fabrics and dyes; Trichromatic dye color light is not standard; Black ink problem of reactive dyes. In the production process, under normal circumstances, the color configuration linearity of the digital ink-jet printing machine for a certain type of fabric is adjusted in advance. If there is no linear color configuration for this fabric, it is required to do color management for this fabric for the digital ink-jet printing machine and generate a linear color management configuration file.
At present, many digital printing machines on the market can adjust the ink drop size, but this adjustment is entirely the overall ink drop adjustment, that is, when adjusting the ink drop 5pl for printing, all nozzles can be supplied according to 5pl; When adjusting the ink drop 50pl for printing, the ink drop size of all nozzles is 50pl. Digital printing can not automatically change the ink jet amount according to different parts of the block surface and lines according to different patterns. This will not meet the differences between different parts of the pattern, and it will greatly reduce the beauty of the pattern. The sizing system is not perfect, mainly because sizing equipment and additives should fully meet the needs of digital printing. Before output, open the steamer and adjust it to the normal working state, take out a small amount of fabric from the pretreated embryonic fabric and put it on the machine, and seal and save the rest. When capturing an image file, you cannot enlarge or reduce the image for output, because the color density and color value of the image will change when it is enlarged or reduced, which will affect the authenticity of the sample. After drying the output sample and steaming, washing and drying it according to the production process of large goods, match the color with the sample and color card, and adjust the color value, color saturation, contrast, color concentration, etc. of each color separation of the image according to the color difference. Then make a sample according to the adjusted image of the proof, proofread it, and then make a sample… Until the sample is perfect. Submit to the customer for confirmation. If the customer does not confirm the customized sample, record the differences and deficiencies proposed by the customer, and then proof until the customer agrees to the next batch production.