Due to the limitation of front and back processes (pre-treatment and post-treatment), most spray printing systems use disperse dyes, and transfer printing is used on chemical fiber fabrics (polyester and nylon), while high-grade fabrics such as silk, cotton and wool are not suitable for transfer printing, so active ink is needed to be directly printed on fabrics.
(1) Printing pretreatment
When the printing machine uses active ink for direct printing, the fabric must be sizing (sizing → drying, and drying temperature should be controlled at 60 ℃), while the pretreatment plays an important role in the final printing effect and quality, so the printing pretreatment process must be paid enough attention.
According to the different printing patterns, we use two different sizes, one is mainly used for printing common patterns, and the most commonly used size, using sodium alginate; the other is used for printing high-precision patterns and characters, using SD-10 size. Sizing equipment is best to use the open width sizing machine, a small number can also be manually sizing.
(2) Digital printing
At present, there are two kinds of printing software in the ink-jet printing system of Tito digital, which can be selected according to the pattern and color matching. For the determination of spray printing accuracy, we use 360dpi and 720dpi for comparison, and feel that 360dpi particles are relatively thick, and the picture effect often fails to meet the customer's requirements, so we choose 720dpi precision for production, and the speed is 2-4m2 / min.
(3) Steaming and coloring
The drum steamer and continuous open width steamer can be selected as the equipment of steaming. Because the drum steamer has the characteristic of bright color, it is recommended to use the drum steamer. (during steam evaporation, the temperature shall be controlled at 102 ℃, steam for 10 minutes)
(4) Washing and finishing
The process of washing and finishing is similar to that of silk screen printing. A certain amount of antifouling agent and fixing agent should be added during washing. After finishing with hot-air stenter, appropriate softener can be added according to the requirements of customers to improve the hand feel.
Requirements of digital printing equipment on site and environment:
Because the piezoelectric nozzle used in the digital printing machine is quite fine and easy to block, there are certain requirements for the site environment. On the one hand, try to arrange it in a dust-proof environment, on the other hand, the site should maintain a certain humidity. According to our experience in practice, the relative humidity should be 45% - 75% ch, generally speaking, the site needs to be equipped with appropriate humidifier. The room temperature is controlled at 19-28 ℃.