The principle of screen printing (also called leakage printing) is to plate the designed disc surface manuscript onto the screen, so that some places on the screen can leak ink, and some places cannot leak ink. This combination is a specific graphic. This principle is a bit like the working principle of a mimeograph machine.
Offset printing is the same as color printing on paper, it is four-color overprinting (printing terminology, I won’t go into details here). That is to say, all patterns are composed of four colors (blue C, magenta M, yellow Y, and black K). And the printing method of offset printing is also different from screen printing. Screen printing leaks ink onto the disc, while offset printing transfers ink to the disc through a circular rubber tube.
Comparing the prices of the two devices, the price of offset printing is higher than that of screen printing. In terms of printing types and quality, there are relatively few types of screen printing. For some large color blocks, screen printing is better, and for some patterns where colors must transition, offset printing is better. For example, when printing a portrait on a CD, if it is monochrome, you can use screen printing, and it will be expressed by dot density just like a black and white photo. If it is in color, only offset printing can do it.
How to tell whether the CD in your hand is screen printed or offset printed? You can touch the printed area on the disc with your hands. If there are obvious bulges (which can be seen as words piled up with ink), it is silk screen printing. If there are no obvious bulges, it is offset printing.
The patterns on clothes are almost all screen printed;
The printing factory that prints cloth is usually called a printing factory, which mainly prints water slurry, that is, water-based oil;
Generally, the patterns on clothes are printed on rolls of cloth. The printing equipment used is organic printing and hand printing. It is recommended that you use hand printing:
1. Manual printing, small factory Fifty thousand yuan is enough; to make these equipment, you can enter: "printing factory" or "printing" online to get a basic understanding;
2. Then recruit a few skilled printers, pulp room masters, The net drying master and several female cloth workers; the film is handed over to the film company for production;
3. The factory building is 200-300 square meters, rectangular (30 meters long is ideal);
4. Can also run: printing leather materials, printing silk flowers, printing other large plastic products, printing glass, etc. It can also be printed on already formed clothes
"T-shirt Design Tutorial" Detailed introduction to T-shirt printing process B
December 1, 2005
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3. Digital direct plate making technology
Digital direct The application technology of computer to plate (CTP for short) in screen printing mainly falls into three categories:
1. Inkjet (wax) CTP plate making. This technology uses a computer-controlled lithographic inkjet or wax-jet printer to print images on a screen pre-made plate that has been coated with photosensitive adhesive in advance. This ink image replaces the role of the plate-making negative, and is made into a printing screen through exposure and development. The United States and Switzerland have both produced and supplied inkjet (wax) CTP plate making machines. In 1992, the American Gerber Company produced a CTP plate making system specifically for T-shirt printing and plate making: Screen Jet (maximum plate making area 65cmx95cm). Hundreds of units have been sold around the world.
2. Spray glue CTP plate making. The difference from inkjet CTP is that it sprays photosensitive polymer glue on the screen. The image is exactly the opposite of that of inkjet. After photosensitivity and curing, it becomes a printing screen.
3. Laser CTP plate making. That is, an optical system controlled by a computer uses a modulated laser beam to scan the prefabricated photosensitive screen. The points scanned by the laser beam are exposed and solidified, and become a printing screen after washing.
Compared with the current plate making technology, CTP technology has obvious advantages. The process of making plate-making negatives has been eliminated, which makes it much more convenient and faster, the quality is also improved, and it is easier to transmit and save data. Its market prospect is very broad.
4. Screen production
1. Screen production materials and tools
The screen consists of a screen frame, a silk screen, and photosensitive adhesive; the materials used There are also screen nails, screen glue, screen sealing tape, etc.; the main tools for making screen plates are: screen stretcher, screen stretcher pliers, screen nail gun, gluing machine, gluing scraper, dryer, and printing plate Machines, water spray guns, etc.
T-shirt printing generally requires a certain number of pattern screens to be saved and the storage period is long. From an economic point of view, screen frames are generally used. The best material for the wooden net frame is fir. If the wood is too hard, it will be difficult for the nail gun to nail the net nails. If the wood is too loose, it will easily deform and loosen. The use of a nailing gun is faster and more convenient than the use of sticky mesh glue, but the stability of the wire mesh is poor. It would be best if the two can be combined. Since most T-shirt printing uses water-based paint, polyester mesh should be used because nylon mesh easily swells and relaxes when exposed to water.
2. Stretching the screen
The requirements for stretching the screen of the T-shirt screen are the same as those of the ordinary screen.
However, it should be noted that the screen mesh selected for different printing materials should be appropriate. For example, if a set of screens contains both water slurry printing material and foaming printing material, gold and silver paste printing materials, the water slurry should use a 120 mesh screen, and the foaming slurry and gold and silver paste should use a 80 to 100 mesh screen. For screen printing, it is recommended to use 140 mesh screen. For printing on fabrics containing chemical fiber or pure fiber, if water-based printing is used, a 140-160 mesh screen should be used, and if ink is used, a screen of 240 mesh or above should be used.
3. Photosensitive plate making
Water-based printing materials use water-sensitive photo glue. Both thermosetting ink-based and solvent-sensitive photo glue can be used. Solvent-sensitive photo glue is better because of the release of film. It's relatively easy. When applying photosensitive adhesive on the screen, attention should be paid to the uniformity of the adhesive layer. Generally, the printing surface adhesive layer is thicker than the scratch printing surface adhesive layer. The thickness of the photosensitive film varies greatly depending on the printing materials, fabrics and graphics.
(1) The film of the screening screen should be printed. If the film is thick, there will be a lot of missed printing material, and it is easy for the dots to be pasted.
(2) Whether chemical fiber fabrics use inks, water-based slurries, or heat-set inks, the film of the screen should be thickened to prevent smearing, and secondly, the printed product will also have a hand-feeling effect due to the thickening of the printing material. Softer. However, if the printed Oxford fabric is thicker (more than 400 denier, used for school bags, travel bags, etc.), the film can be thicker accordingly.
(3) The screen glue layer for glue printing and foam printing must be thick. Especially when printing glue on dark fabrics and rough fabrics, the screen glue layer should be about 3 times the thickness of the screen glue layer (more than 0.3mm). In this way, the printed glue will have strong covering power and The printing surface is smooth and clean. The production and process requirements of T-shirt printing screen printing are basically the same as those of conventional screen printing. However, since glue printing uses a screen of about 80 mesh and is a thick film, pay attention to the exposure time when printing the screen to avoid The edges of the image appear jagged. The pre-press process not only determines the quality of T-shirt production, but also determines its success or failure. In business, a T-shirt with a beautifully designed image can still be sold even if the printing is not very fine, because few consumers know the printing technology; but if the pattern of a T-shirt is not well designed, , no matter how fine your printing is, no matter how good the quality of the fabric is, no one will buy it. Because buying a T-shirt is buying culture, and the value of the T-shirt pattern exceeds the value of the T-shirt blank. Therefore, the design of T-shirt graphics plays an important role in the value composition of T-shirts. Of course, this does not mean that printing quality is not important. For T-shirts with high printing quality, even consumers who do not understand printing technology will be able to distinguish the quality of T-shirts based on their feelings. We have summed up a sentence in practice: the pattern determines whether it can be sold; the printing determines whether it sells well (price).
In addition, in terms of printing exposure, our company usually does not have very precise requirements for exposure time. However, if you use the printing test table for experiments, you will find that the control of printing time is very important for thick lines. It may not have a big impact, but it has a great impact on fine lines and screen dots. If you want to produce a high-quality screen printing plate, you must carefully determine the exposure time. It is the same set of four-color screened negatives. Due to the different dot densities of each color, the exposure time should also be different. The exposure time of the low-key screen should be slightly shorter, and the exposure time of the high-key screen should be slightly longer to avoid the highlight dots being washed out. . Except for computer production, it can be said that the prepress process is not difficult to master. The important thing is to be serious and strive for excellence. Published in "Screen Printing" Issue 1, 2000. T-shirts can be classified from two aspects: business scope and printing technology.
T-shirts can be classified from two aspects: business scope and printing technology.
T-shirt classification:
1. Commodity T-shirts - T-shirts that are targeted at social consumers and enter regular commodity circulation channels.
2. Advertising T-shirts - T-shirts designed to carry advertisements are a type of advertising media. Their content can be commercial advertisements, political advertisements, public service announcements, etc.
3. Travel T-shirts - Travel T-shirts have a considerable status in the foreign tourist souvenir market. Tourist destinations, historical sites, and cultural landscapes must be accompanied by a large number of travel T-shirts and T-shirt shops. Travel T-shirts can best reflect national culture, regional culture, customs and customs, natural landscape culture and political and historical culture.
4. Group T-shirts - From large international social organizations to small teams and bands, having your own T-shirt always makes people proud.
5. Theme T-shirts - Major historical themes, cultural and entertainment projects, political activities, and celebrity anecdotes will also be reflected on T-shirts to satisfy people's desire to participate and commemorate. Recent themes such as the 1997 Hong Kong return theme and the 1998 World Cup theme have brought about a huge T-shirt trend and achieved considerable social and economic benefits.
6. Branded T-shirts - Many famous brand clothing often produce their own branded T-shirts to achieve both fame (advertising effect) and profit.
T-shirts can be classified as follows according to printing:
1. Partially printed T-shirts - the main printing parts are: front body, back, upper left chest, cuffs, lower back collar, etc. . Partially printed T-shirts account for more than 70% of the total number of T-shirts
2. Full-body printed T-shirts - Full-body printed T-shirts are divided into three categories: cloth printing, cut-piece printing and garment printing. Among them, full-body printing on ready-made garments requires the use of specialized T-shirt printing machines. Such machines currently represent the highest level of technical equipment for T-shirt printing.
3. Water-based pigment printing - mainly used for white T-shirt printing.
4. Glue printing - mainly used for dyeing T-shirt printing.
5. Thermosetting ink printing - suitable for all kinds of fabrics (including chemical fiber), it is the most promising T-shirt printing ink because it is suitable for the use of advanced computer design and modern printing ink. The automatic production method symbolizes the trend of contemporary scientific and technological development. Especially when printing screen patterns on dark fabrics, the effect is unmatched by glue, which has accelerated the withdrawal of glue from the field of T-shirt printing.
6. Transfer printed T-shirts - there are two main types: hot melt adhesive type and deinking penetration type.
7. The main types of special paint printing are gun pulp printing, flocking printing, photosensitive, water-sensitive, heat-sensitive paint printing, luminous paint printing, scented paint printing, and colorful decorative films (laser films) Printing etc.
8. Special process processing - such as resist dyeing printing, discharge printing and batik, tie-dye T-shirts, etc.
9. Embroidered T-shirts
10. Composite technology - that is, the above various printing and processing technologies are combined into a T-shirt pattern. What are the pixel requirements for thermal transfer images and materials? ? [When editing cup pictures and shirt patterns, first set the size of the production. The resolution is generally 200-300. Regarding the selection of picture materials, we recommend that it is best to use 3 million pixel digital photos. For pictures or photos downloaded from the Internet, it is usually 75.