Liquid ink jet printers provide an economical method for screen printing companies to enter the wide-format graphics digital production market. However, these printers require a special coating medium that can accept ink jets. For screen printers, most media that have not been previously coated have been used. Matching the inks used in the job to the media is a challenging task.
For low cost, high resolution liquid ink jet printers, coated media must be used. If a non-coated material is used, the image quality or use characteristics required for the final pattern cannot be obtained.
The basic function of receiving ink jet coating is to absorb, hold and dry each ink droplet. That is to say, the main purpose is to optimize the formulation of the paint so that the ink droplets are dried in the desired size and shape. To feel what is happening when printing images on non-coated paper, it is conceivable to drop a drop of food coloring agent on the paper towel. The droplets spread uncontrollably irregularly on the paper towel and penetrate the paper towel. The same thing can happen with printing on non-coated materials, but it is not so serious. The result is a large and irregular dot, and naturally the image quality is also poor.
When printing on uncoated or unsuitable coating materials, the common situation is:
1. Drops of ink (ink ink droplets spread open);
2. The ink penetrates the substrate material (the ink is over absorbed and penetrates to the back of the substrate);
3. Reduced color density;
4. Tonal range is reduced;
5. Speckles appear in the image;
6. The medium wrinkles;
7. Extended drying time.
The formulated paint will capture the ink droplets to “solidify” in the optimal size and shape to achieve the best image density and color quality.
In addition to these basic requirements, the market's need for more advanced formulations for different applications has also contributed to the development of coatings. For example, ink jet photo media is mainly used for photo enlargement and photo effect graphics. The coating on these materials controls dot gain and allows the ink to adhere tightly to the surface of the substrate, resulting in optimal image quality, and the output image is very close to the traditional photographic image.
On the contrary, the material of outdoor flags requires that the paint should not only provide good image quality but also withstand long-term outdoor exposure. Therefore, the paint used for the flag needs to draw ink from the surface of the flag and seal the ink in the paint, so that the graphics on the flag are durable, and the outdoor use time is 1 year or more.
There are four basic types of coatings for media used in liquid-fed inkjet printers. Most coatings can be applied to two types of print heads (thermal and piezoelectric) for inkjet printers. Which kind of paint can produce the best effect, the most influential factor is the type of ink - dye ink or pigment ink.
Anticorrosion Pigments, Inkjet Receptive Coating, Matting Agent,PET
