1. Roller printing
The process of printing on the fabric with a copper cylinder engraved with a concave pattern is called cylinder printing. When drum printing is printed on the fabric, the color paste is transferred to the fabric to obtain the printed pattern.
2. Digital printing
Digital printing, printing using digital technology. Various digital patterns processed by scanning, digital photography, image or computer are input and calculated, and then processed by computer color separation printing system. There is a special RIP software, which directly sprays various printing dyes (active, dispersed and selected ink coatings) between its jet printing systems onto various fabrics or other media, and after treatment, various high-precision printing products are obtained on various textile fabrics. The digital printing process can be subdivided into the following categories.
I. Classification by printing method
Digital printing is the floorboard of inkjet printing technology. In order to explain various printing methods and characteristics more clearly, this paper introduces all-round and multi-type digital printing and process decomposition of textile fabrics.
1. Digital Direct Jet Printing
Digital direct jet printing method is suitable for disperse, acid dyes, coatings and reactive inks. Digital direct jet printing is a process of direct jet printing on pulped semi-finished textiles. The technological process is as follows: according to the textile, select the corresponding ink, design the pattern and size, then spray print directly on the textile direct jet printing machine, and then dry, steam, wash with water, dry, soften and set (the paint can be fixed only by baking).
2. Heat transfer mode
Thermal transfer is to print textile dyes on paper (coating) first, and then transfer the patterns on paper to textiles with thermal transfer machinery. The advantage is that the accuracy is relatively high, but the printing efficiency is low. Only fabrics with high polyester or polyester content can be made, and the transfer fabrics are semi-finished products without softener (adding softener may affect the dye uptake).
3. Hongmao Road
Like thermal transfer, textile dyes need to be printed on paper first, and then printed on paper and fabric with special machinery to realize pattern transfer.
There are two ways to treat the fabric after embossing:
Firstly, traditional processes such as steaming, washing and setting are carried out;
The second is to fix the color by cold reactor chemical reaction (the fabric needs to be chemically treated in advance). Using reactive, disperse and acid dye inks, this process is suitable for fabrics other than blended fabrics.
Second, according to the dye and process classification
1. Distributed digital printing
At present, more than 50% of printing inks in China are disperse dye inks, which are used for printing chemical fiber fabrics such as polyester fibers. Disperse dyes are a kind of nonionic dyes with low water solubility, which exist in water in a highly dispersed state of fine particles with the aid of dispersants during dyeing.
2. Dynamic digital printing
Reactive dye ink accounts for about 29%, mainly used for silk and cotton fabric printing; Reactive dyes, also known as reactive dyes. It is a dye that reacts chemically with fibers when dyeing. The color separation of these dyes contains genes that can react chemically with fibers. When dyeing, the dye reacts with the fiber to form a valence bond between them, forming a whole, which improves the fastness to washing and rubbing. Active fuel molecules include parent dyes and active groups, and the groups that can react with fibers are called active groups. At present, it is mainly used for weaving and knitting fabrics such as cotton, general anesthesia and silk. Or a fabric with a high content of the above components.
3. Acid digital printing
Acid dye ink has a small specific gravity, accounting for about 7%, and is used for printing wool, nylon and other fabrics. Acid dyes are a kind of water-soluble dyes with acid groups in their structures, which are dyed in acid media. Most acid dyes contain sodium sulfonate, which is soluble in water, bright in color and complete in chromatography. It is mainly used for dyeing wool, silk and nylon, and can also be used for leather, paper and ink. Generally, there is no coloring ability for cellulose fibers.
4. Pigment ink digital printing
The domestic pigment ink consumption is less than 2%, and most of them are foreign products. Manufacturers include Huntsman, BASF, DuPont, Klein and other companies.