Brief Introduction Of Four Color Dot Printing Technology

1、 Online edition Material Science choice

1. Wire mesh: select 200-350 mesh monofilament polyester yellow wire mesh in central China. Because when the white screen is exposed, the light will refract and the high light level of the pattern will lose the material market. The extension rate of the screen must be lower than that of the printing union. In order to avoid moire, it is best to choose the mesh number of the screen as 5-6 times the number of dot division dot lines in central China.

2. Photosensitive adhesive: Select photosensitive adhesive materials with high solid content, good resolving power, and good bridging and adhesion with the screen. This can ensure that the highlight dot will not be lost during exposure, high definition, high-resolution screen.

2、 Screen making

1. Electrosplitting: Submit the original to be printed to the unit that holds the computer screen printing color separation plate making system for image scanning, layout design and production, until the electrosplitting equipment supplies are output. It is better to select 35-80 lines/inch as the frequency modulation dot of the electrographic negative, and the photosensitive film is located on the front of the negative in the middle of China. The number of mesh lines selected for the electrographic negative should be related to the size of the printed product and the distance between the printed products through visual inspection in central China. Generally, advertising production pays attention to the effect of far seeing (more than 1m beyond the visual distance). The number of mesh lines selected is 35-40 lines/inch, and the screen selection of 200-300 mesh is the best printing technology. Such as printed decorative cloth, bedding, children clothing Fabric, high crotch adult Clothes & Accessories , tourism products, etc spin Printing tools. Textile printing of flowers, cartoons, landscape patterns, handicrafts, traditional Chinese paintings and oil paintings can be easily printed in central China. Of course, for these printing, the number of dot lines should be higher. Generally, 65, 70, 80100 line printing tools should be used.

2. Straightening: the method of oblique stretching is used. Usually, the dot angle of each color is 90 degrees for yellow printing, 75 degrees for blue printing, 15 degrees for red printing, and 45 degrees for black printing. If the mesh size of the screen exceeds 5-6 times of the dot splitting mesh size, the straight stretching method can also be used in central China. This can prevent the troublesome moire phenomenon often encountered in the four color screen printing. The most important rule of stretching the screen is that the screen tension in the four printing screen frames should be the same. If the tension is different, the stretching length of the screen in the printing process will be different, which will lead to the misregistration of the printing market.

　　3， coating Photosensitive glue: first wash the four screen frames with detergent or screen cleaning solution, and then use a sizing machine with sharp blade after drying. The width should be close to the inside of the screen plate, and the force should be uniform. First coat the scraping surface once, then reverse the screen from top to bottom, and then coat the scraping surface once. Use the same method to coat the printing surface twice. The film thickness of - 20 μ m is the best printing market. Sizing should not be too thick, otherwise the dot is easy to spread the printing technology. After coating, place the screen horizontally, dry it at no more than 30 ℃, and then blow it with a fan. The working darkroom environment should be clean and dust-free.

4. Printing: When printing, the bottom of the negative film should be close to the glass. It is better to use a vacuum printing box, and the printing box should use float glass to reduce refraction, otherwise the screen definition and resolution will be affected in central China. It is better to use a revision box when pasting negatives. First, 100% align the regular lines of the four negatives. The backer shall be set on the edge of the revision box in advance, which shall be consistent with the official platform printing backer. Use transparent double-sided adhesive tape to fix and screen separately, and then put it on the photosensitive platform to expose central China. In this way, when it comes to official printing, the matching will save much effort in the material market.

5. Development and development: first wet both sides of the screen with tap water, soften for 1-2 minutes, and then use a small high-pressure water gun to wash the printing surface. The pressure should not be too high when washing until the screen reproduces the negative printing alliance. Then rinse both sides of the screen with tap water until no softened photoresist residue remains. Dry the screen, repair the pinholes and re expose it to increase the durability printing market of the screen.

3、 Printing

1. Printing machine: The flat screen printing machine is the most important hardware to improve the printing effect. The flat screen printing machine with high alignment accuracy is selected for four-color screen printing in central China. The printing table must be flat with printing tools.

2. Scraper: In order to obtain high-quality printing products, the scraper printing market with hardness of 70 degrees should be selected. The printing squeegee surface should be smoothed with a squeegee, and the edges should be in a linear shape. The effective scraping angle is about 70 degrees for printing tools. The pressure of printing scraper should be adjusted to consistent printing technology.

3. Size: MD-994 four-color dot ink is selected. The new product has good thixotropy, PH value of 7-8, and is also equipped with auxiliary adjustment: original size diluent, standard color type darkening agent, blocking agent, basic original size, primer printing technology.

4. Printing: the plate sequence is yellow, blue, red and black. At the beginning of plate alignment, the black plate shall be printed first, and then the plates shall be aligned one by one. After the four-color screen plate is aligned correctly, the printable printing tools shall be placed.

5. Manual printing and machine printing: If large quantities of manual printing are required, four hand touch strength operators should be selected to test print the printing tools first. printing The platform must be flat printing technology. It is particularly noted that the screen distance (i.e. the distance between the screen plate and the platen) should be controlled between 2-3MM. It is particularly emphasized that the speed of scraper printing also affects the printing effect. Therefore, the speed material market must be determined according to the fineness of the four color screen printing pattern and the background color, moisture absorption and surface structure of the printing material. Compared with the original color manuscript, all aspects of the debugging are correct before the official printing technology.