Digital printing is a general term for ink-jet printing technology. In order to explain various printing methods and characteristics more clearly, this section only introduces all-around, various types and process decomposition of digital printing of textile fabrics.
By printing method:
- Digital direct jet printing: it is a direct jet printing method for the sizing of semi-finished textiles. This method is suitable for coating, reactive, dispersive and acid dye inks. The process is as follows: select the appropriate semi-finished fabrics (without softener) according to the ink category, carry out the sizing, drying, and rolling process, and then go to the digital equipment for direct printing (the fabrics are treated as paper), and then carry out drying, steaming, washing, drying Processes such as softening and setting (in which the paint can be fixed as long as it is baked)
- Cold transfer printing: it is a printing method in which textile dyes are first printed on specially coated paper, and then the patterns are transferred to textiles by a cold transfer machine. This method is suitable for all kinds of fabrics except blending. The inks used include reactive, disperse, acid, and other dye inks; The method also requires semi-finished fabrics to be embossed with printed paper. There are two ways to treat the embossed fabric. One is to conduct a cold pile chemical reaction to fix the color (the fabric needs to be chemically treated in advance); Second, traditional steaming, washing, shaping, and other traditional processes shall be carried out.
- Heat transfer printing method: it is a printing method that prints textile dyes on specially coated paper, and then transfers patterns to textiles through heat sublimation. This method is similar to traditional paper printing. It can only be used for polyester or high polyester-containing textiles. The transfer fabrics are all semi-finished products without softener (the softener may affect the coloring rate).
Classification by dye and process
- Distributed digital printing
At present, more than 50% of the printing inks in China are dispersing dye inks, which are used for the printing of polyester fiber and other chemical fiber fabrics; Disperse dyes are a kind of non-ionic dyes with low water solubility, which exist mainly in a highly dispersed state in water with the help of dispersants
- Active digital printing
Reactive dye inks account for about 29%, mainly used for printing silk and cotton fabrics; Reactive dyes, are also known as reactive dyes. It is a kind of dyestuff that reacts with fiber during dyeing. This kind of dye separation contains genes that can react with fibers. When dyeing, the dye reacts with fibers, forming a covalent bond between them as a whole, which improves the fastness of washing and rubbing. Reactive fuel molecules include two main components, a parent dye, and a reactive group. The group that can react with fiber is called the reactive group. At present, it is mainly used in woven and knitted fabrics such as cotton, general hemp, and silk, or fabrics with high content of the above ingredients.
- Acid digital printing
The proportion of acid dye ink is small, accounting for about 7%. It is used for printing on wool, nylon, and other fabrics. Acid dyes are a kind of water-soluble dyes with acid groups in the structure. They are dyed in an acid medium. Most acid dyes contain sodium sulfonate, which can be dissolved in water, with bright color and complete chromatography. It is mainly used for dyeing wool, silk, and nylon, as well as leather, paper, ink, etc. It generally has no coloring power over cellulose fibers.
- Pigment ink digital printing
Most inks are foreign products, and the manufacturers include Huntsman, BASF, DuPont, Klein, and other companies.
Classification by fabric composition:
- Digital printing is based on cotton, but reactive dye ink can also be used for hemp, silk, etc;
- Digital printing is mainly based on chemical fiber, and digital printing is produced with dispersed thermal sublimation dye ink and chemical fiber disperse direct injection;
- Some blended fabrics such as t/c, which cannot be operated with reactive, dispersed, and acid dye ink, shall be printed with paint ink;
- Digital printing based on nylon and wool is produced with acid dye ink, and silk can also be used.