What are the common problems and solutions of printing Ⅱ

5. Reasons for the skinning phenomenon of the glue during the printing process

Any printing material has a common characteristic, that is: the thinner the ink layer, the faster the drying, and the same is true for the glue. Since the screen is larger than the pattern, there is enough space for the paste in the screen to be stacked, and it is impossible for the squeegee to clean the paste every time it is printed. Especially, a thinner ink layer is often generated above the pattern. The ink layer will form a semi-dry film in a short period of time, and these films are brought into the partial holes by the squeegee to block the mesh holes, resulting in local blockage.

Solution:

Use wooden strips to isolate the pattern area of the screen from the screen frame to control the slurry within a certain range. The squeegee can clean the slurry on the edge of the screen pattern every time, which means that the slurry is within this range. It is impossible to produce a thin layer of ink inside, so that the phenomenon of skinning can be eliminated.

6. Reasons and solutions for the seepage of the paint paste prepared by yourself

Self-made paint pastes are water-based pastes for textile printing. Infiltration (bleeding) can be found from the following aspects.

(1) Synthetic fiber fabrics: such as polyester, nylon, polypropylene, etc., or blends with a high proportion of synthetic fibers. Synthetic fiber: The fabric is a hydrophobic substance, and the water-based slurry of the coating used for printing cotton fabrics is easy to permeate and smear. When printing synthetic fabrics, thick emulsified paste should be used when mixing the pulp to avoid dilution with water. If it must be diluted, it should be diluted with a thin emulsified paste. Do not dilute directly with water.

(2) The humidity in the air is too high, such as long-term rainy weather in the south, less or no water should be added when mixing pulp.

(3) Cotton fabric is a natural cellulose fiber fabric, which is a hydrophilic substance. Generally not easy to permeate. However, if the capillary effect is too high, it will also lead to osmosis. Therefore, the appropriate capillary effect is controlled at about 7-8cm. Before feeding, it is crucial to ask the manufacturer's technical indicators. If the capillary effect is too low, it will not be printed, and if the capillary effect is too high, it will cause permeation.

(4) Some enterprises use emulsified paste as thickener, commonly known as A-gang paste. It is emulsified with white kerosene, peregrine and synthetic dragon glue under high-speed stirring. If the A-gang pulp has quality problems and is not fully emulsified, there will be "oil circles" after printing, which will easily cause misunderstandings of "bleeding" or "watermarks". Therefore, good quality A-gang pulp should be used or a synthetic thickener should be used to overcome the occurrence of "oil ring".

(5) There are many comprehensive factors that cause "seepage" and "bleeding", such as the texture of the texture is too thin, too thin, and too light; the pattern area is too large; the mesh number is too low; the pressure during operation is too large; Does not correspond to the pattern, the amount of sizing is too large and so on.

In addition, the countertop also has a lot to do. If you use glass or plastic veneer with a very smooth hard surface, it will also cause seepage of the pallet. The outline is not clear, but should be changed to a flexible soft countertop.

7. How to mix pastes of different colors?

Color science is a deep knowledge, and color matching requires the accumulation of practice. Learn the theory well, be brave in practice, the splendid and colorful will belong to you. A good colorist seems to be able to roughly determine the basic formula of color matching. There are even some old color grading technicians. When the mass production is about to come out, they find problems and add color materials in time. It is too late to make samples. Basic skills.

First, the secondary colors are adjusted from the three basic colors of red, yellow, and blue: orange, green, and purple. Then modulate three colors: yellow gray, blue gray, red gray.

Then, each single color in each set of chromatograms from light color to medium color to dark color, the dosage is 0.1%, 0.5%, 1%, 3%, 5% respectively, and the formula of the sample sticker is scratched and printed.

In addition, each batch of business samples and formulas should be kept on file for reference, and perseverance will surely yield results.

The general principles of color matching are as follows:

Minimize the number of dyes or paints used in color matching. One can be used, but no two, and two can be used, but three. In order to facilitate the control of color and light, generally three or less color matching is better. The second is the same type of dyes or coatings. It is best not to mix different brands of different manufacturers. If it is necessary to use the "coloring head", then the "coloring head" can only be very small, and the two brands cannot be equally divided.

Another principle is: dyes or paints have their saturation values, and if they exceed their saturation values, they are easy to be washed off and stained. Even if the paint is black, the dosage should be controlled at 8%-10%, not more than 10%.