Brief description of outdoor screen advertising and pattern screen printing technology

1, the main features of screen printing

Screen printing has features that other printing methods do not have, namely:

● The ink of the substrate is very thick;

● can use a variety of ink printing;

● The printing pressure is very small;

● The layout is soft.

Therefore, the scope of application of screen printing is very extensive. For example, outdoor signboards, billboards, road signs, and various decoration items related to commercial art can be applied to screen printing. In addition, because screen printing products have vivid color effects and excellent light resistance, they are suitable for long-term outdoor advertising and expressive and eye-catching posters and posters. At the same time, because the thickness of screen printing ink layer and the advantages of using various inks, it is very suitable for printing products with high visual effect requirements.

Halftone Screen Making Points

Coloured manuscripts with shades of tones need to be coloured and screened for colour and shade reproduction. Different from other printing methods, the color separation and screening of screen printing have certain requirements and conditions.

For example, in screen-screening, screen printing is difficult to copy over 100 lines/inch (1 inch = 2.54cm) or more. Therefore, 55 line/inch, 60 line/inch, and 80 line/inch magenta contact screens are often used. If you use a thin wire like 150 lines/inch to touch the screen, you can enlarge the negative film 2x to 3x and make a 75x/inch mesh positive film as a film. In addition, when the monochrome screen angle is 45°, the two-color screen angle should be slightly staggered so as to avoid moire after development. In the case of four-color printing, the screen angles of magenta, cyan, and black colors are staggered by 30°, and the insignificant yellow color is in the meantime. The screens and mesh negatives that stretch on the frame will also have a moire pattern. The number of screen meshes should be higher than 4 times the number of screens to avoid this problem.

1) Films

a. Photo or artwork pattern using electronic separation or photographic color separation technology to produce halftone film (the number of screens is 50-80 lines/inch

Inch), sub-yellow, product, blue, and black four-color positive figures.

b. The text drafts are produced using phototypesetting or hand-painted black-and-white draft photographing methods.

c. The manuscripts and designs were imposed according to the platemaking requirements and became a film for printing.

2) Network Edition

a. Select the screen size and the number of meshes according to the number of screens in the film layout.

b. Prepare the number of frames according to the requirements for overprinting.

Monochrome printing: 1 frame

Two-color printing: 2 frames

Tri-color printing: 3 frames

Four-color printing: 4 frames

The tension of the stretch of each frame was measured with a tension meter and kept basically the same.

C. Photosensitive adhesive coating should be thin and even, the thickness is generally 8 ~ 10μm.

d. When printing, make the screen line and the screen latitude and longitude have a certain angle, usually 30 ~ 45 °, to avoid moire after development.

3. Printed materials and printability, durability

1) Printing materials

Choose special printing paper that is similar to coated paper and translucent, or use PE, PP, PC sand surface translucent plastic film or plastic film base. 2) Ink

The difference from general printing inks is that, under the irradiation of transmitted light, screen printed halftone prints should produce similar reversal film effects; the use of transparent ink is a common method. In addition, different printing materials should choose different printing inks for the transparency of printing materials.

3) Printability

The printability should consider the following two points:

● Printing workability;

● printing effect.

4) Durability

Durability should consider the following points:

● Hue, gloss retention;

●Lightfastness;

● weather resistance;

● physical strength;

● secondary processing;

● toxicity and other.