The business model of “Three High and One Low” (high consumption, high pollution, high emission, and low added value) of the traditional printing process has been depressed in the market. The characteristics of low pollution, low consumption, high added value, and flexible production of the digital printing process conform to the trend of green, environmental protection, and sustainable development. At the same time, it also caters to the fast fashion of “small-batch, multiple varieties and short delivery period”, which is in line with the mode transformation and development direction of the printing industry in the future.
As a process evolved from the traditional printing process, digital printing has been widely used in the fields of clothing, home textiles, industrial textiles, and so on. It can be printed on cotton, wool, silk, hemp, polyester, nylon, and other fibers and blends. It is conceivable that digital printing processing has a very broad prospect. It is a rare high-profit industry in the current market, attracting many investors to enter this field one after another in order to get a big return. Experts predict that the next few years will be a golden period for the development of digital printing processing in developing countries.
Why can digital printing replace screen printing? What are the differences between the two printing processes? The following article will give you an in-depth analysis of the technical characteristics and development prospects of digital printing and screen printing.
Printing is a process in which dyes or paints are sprayed onto the fabric surface according to the preset patterns. With the development of printing technology, a pattern has been formed in which screen printing, rotary screen printing, roller printing, digital printing, and other printing processes coexist. The application scope of various printing processes is different, the process characteristics are different, and the printing equipment and consumables used are also different.
As a traditional classic printing process, screen printing has a wide range of applications, covering almost all products that can use printing technology, accounting for more than 90% of the printing industry. In recent years, digital printing has been developing rapidly, and many people in the industry feel that digital printing will replace screen printing technology. What are the differences between the two printing processes?
There is little difference in the types of printing materials
Digital printing processing is divided into five categories: acid digital printing processing, active digital printing processing, paint digital printing processing, dispersed heat transfer printing, and dispersed direct-injection digital printing processing.
Acid ink for digital printing is suitable for protein fibers such as wool, silk, and nylon fabrics.
Digital printing processing reactive dye ink is mainly applicable to the digital printing processing of cotton, hemp, viscose fiber, silk, and other fabrics, and can be applied to the digital printing processing of natural fiber fabrics such as cotton fabric, and silk fabric, wool fabric and so on.
Digital printing process coating ink is suitable for digital ink-jet printing of cotton fabrics, silk fabrics, chemical fiber, blended fabrics, knitted fabrics, sweaters, towels, and blankets.
Digital printing heat transfer ink is suitable for transfer printing of polyester, non-woven fabrics, ceramics, and other materials.
Digital printing processing direct spray disperse ink is suitable for digital printing processing of polyester fabrics, such as decorative cloth, flag cloth, banners, etc.
Compared with digital printing, the traditional printing process has little advantage in the types of printing materials. The first reason is that the traditional printing process has limitations in the size of printing pairs, while the ink-jet width of large-scale industrial cotton and hemp direct jet belt conveyor can reach more than 3 meters at most, and it can print without limit. Even one belt conveyor can form an assembly line to integrate all processes; The second is that in some materials, the performance of the traditional water-based ink printing process is slightly backward, so only solvent-based ink can be used for printing. The digital printing process can use water-based ink for ink-jet printing on any material, thus avoiding a large amount of flammable and explosive non-environmental friendly solvents in the production process.
There is little difference between the traditional printing process and the digital printing process in the types of printing materials. However, there are limitations in the size of the traditional printing process; On some materials, the traditional printing process can only use flammable and explosive non-environmental friendly solvent ink for printing, while the digital printing process is not subject to this restriction.
Differences in color
The greatest advantage of digital printing processing mainly focuses on the fineness of color and pattern, which can not only highly restore the primary color, but also the fineness of the pattern. From the perspective of color, the inks used in the digital printing process are divided into dye ink and pigment ink. In the degree of bright color, dye ink is better than pigment ink.
The process of digital printing can be divided into acid digital printing, reactive digital printing, dispersed heat transfer printing, and dispersed direct-injection digital printing. They all use dye ink for processing.
Although pigments are used as colorants in the process of pigment ink digital printing, they all use nano pigment pastes. For specific links, as long as the ICC curve is well matched, the color display can reach the extreme.
The color of the traditional printing process is controlled by four-color dot matching and pre-press ink color matching. The color display power is far lower than that of digital printing. In addition, in the process of digital printing, the pigment ink adopts nano pigment paste, and the dye in the dye ink is water-soluble. Even for the dispersed thermal sublimation transfer ink, the pigment is also nano. In contrast, the color of digital printing processing is more bright.
Therefore, the boss who wants to invest in the printing processing industry gives priority to digital printing processing. If it is a traditional printing processing plant, it is recommended to upgrade and transform the production mode.
Differences in patterns
The traditional printing process requires negative plate making first. The errors in the plate-making process and the mesh size of the screen have an impact on the fineness of the pattern. Theoretically, the smaller the screen aperture is, the better. But ordinary printing uses a 100~150 mesh screen, and the mesh number of four-color dots is 200 mesh. The higher the mesh number, the greater the probability of blocking the screen with water-based ink, which is a common problem. In addition, the accuracy of the plate during scraping printing has a great impact on the fineness of the printing pattern. Machine printing is relatively better, but manual printing is more difficult to control. Obviously, color and fine graphics are not the advantages of traditional printing technology.
The pattern fineness of digital printing is related to the characteristics of the inkjet print head and printing speed. The smaller the ink drop of the inkjet print head is, the higher the printing accuracy is. The ink drop of the Epson micro piezoelectric print head is the smallest. Although the ink drop of the industrial head is larger, it can also print images with a precision of 1440 DPI. In addition, the faster the printing speed of the same printer, the smaller the printing accuracy.
Advantages of the traditional printing process
The advantages of traditional printing lie in special printing pastes, such as gold, silver, pearlescent, crack effect, bronzing flocking effect, suede foaming effect, etc. The traditional printing process can print a 3D stereoscopic effect. It is difficult to make white ink in digital printing. At present, white ink is mainly maintained by imported ink, but printing on dark cloth is impossible without white, which is the difficulty that needs to be broken through in popularizing digital printing processing in China.
Digital printing products are soft while traditional printing goods have high color fastness
The main properties of printing products include surface properties, i.e. hand feeling (softness), stickiness, resistance, color fastness to rubbing, and color fastness to soaping; Environmental protection, i.e. whether it contains formaldehyde, azo, pH, carcinogenic aromatic amines, phthalates, etc.
In the traditional printing process, except for water slurry and discharge, other types of printing have a strong coating feeling, which is due to the high resin content as a binder in the printing ink formula and the relatively large amount of ink. The digital printing process has no coating feeling, and the printing is light, soft, and sticky. Even in the process of pigment digital printing, because the resin content in the formula is very small, it will not affect the hand feeling. Acid digital printing processing, active digital printing processing, dispersed heat transfer printing, and dispersed direct jet digital printing processing, are uncoated and do not affect the hand feel of the original fabric.
Whether in traditional water-based printing ink or pigment printing ink, the resin is used as adhesive, on the one hand, it is used to increase the adhesion fastness between coating and fabric, so that it is not easy to crack and fall off after washing; On the other hand, the resin can wrap the pigment particles, so that it is not easy to decolorize. The resin content of traditional water-based printing ink and size is 20%~90%, usually 70%~80%, while the resin content of pigment printing ink in digital printing processing ink is only 10%. Obviously, theoretically, the color fastness to rubbing and soaping of the digital printing process will be worse than that of the traditional printing process. In fact, the color fastness of digital printing without certain post-treatment is really poor, especially the wet rubbing color fastness. Although the color fastness to soaping of the digital printing process can sometimes pass the test according to Gb/t 3921-2008 Textiles – Tests for color fastness to soaping, it is still a long way from the water fastness of the traditional printing process.
Without certain post-treatment, the rubbing color fastness of digital printing is really poor, especially the wet rubbing color fastness. There is still a certain distance between the soaping fastness of digital printing and the washing fastness of the traditional printing process. At present, the color fastness of rubbing and soaping needs further exploration and breakthrough.