Why we need to do DTG pre-treatment before printing dark T-shirts?
Nowadays, digital printing is very important. In pure cotton printing, besides the traditional screen printing, digital printing has been accepted by market and becomes more and more popular by his fast producing, high expression and personality customization.
The main application of digital garment printing is the T-shirt printer, which can directly print the pattern on the finished T-shirt (sweater). It is easy to set up a t-shirt printing factory, just buy a printer with some auxiliary equipment, which can help you to do DIY t-shirt for some commemorative occasions, trade fairs, public welfare activities, to show the company culture and team image better.
For common T-shirts, there will be a variety of colors, mainly divided into two categories: white T-shirts and dark T-shirts (such as black, red, blue, etc.). It is easy to print on white fabric for the digital printing, sometimes you can print directly. When printing of dark cotton fabric, the common way is to spray a white base firstly in order to make the pattern shows better effect. How to make the white base? There are two ways.
1, Use the screen printing paste to scrape the white base, then print the pattern on the white base:
1) Plate maker: white pattern screen plate.
2) The speed is faster. Generally speaking, the printing speed of the direct garment printing will be slower then screen printing .
3) The cost is lower. For example, the price of DuPont’s white ink is high, and the price of the screen printing paste is lower.
2, Use the double-heads printing technology, first printing the white ink directly on the dark fabric, then printing the color ink.
1) Directly printing, do not need to make plate, the production process is simpler.
2) The color ink printing is right after the white ink printing, so the positioning is more precise.
3) Even one piece t-shirt printing is available.
As the main component of the white ink is titanium dioxide, it is inorganic chemistry, does not have physical viscosity. It is very difficult for the cotton t-shirt to have a chemical reaction and then firmly adsorbed with it. If the T-shirt does not do a treatment before printing, the color fastness will become very bad. The t-shirt can not be repeatedly water washed, easy to fade.
But if you do not print the white ink as a base because of above reason, the pattern cannot be shown when you direct print on dark T-shirts. It is necessary to use a white coating with strong covering power to cover the color of the fabric itself. Just like applying a foundation to the skin, you can make a better makeup.
Therefore, if you want to print dark t-shirt, you must follow the below steps to strengthen the fastness of the pattern: 1. Spray the coating liquid. 2. Print white ink.
The coating liquid to the t-shirt, just like some “Medium”. The ink can not be printed directly to the cotton fabric to achieve the water washing requirement of fastness, so we need the “Medium”, which can be adsorbed onto the fabric and the pattern. To ensure the printing quality and fastness requirement, uniformly spray the coating liquid is very important.
There are some ways to spray the coating liquid：
Disadvantages: Hard to control the dosage of liquid and may cause some waste.
2）By watering can
Disadvantages: low work efficiency, spray liquid scattered in the air, bad for health.
3）By T-shirt pre-treatment machine
1) Closed working, high safety.
2) Electric control system, speed fast.
3) Keep the dosage of spray consistently.
4) Nice appearance, suitable for T-shirt printing shop.