Screen printing consists of five elements, namely screen printing plate, scratch board, ink, printing platform and substrate. The basic principle of screen printing is: use screen printing plate part of the mesh through ink, non-text part of the mesh through ink basic principle of printing. When printing ink is poured on one end of the screen plate, use the scratch board to apply some pressure on the ink part of the screen plate while moving towards the other end of the screen plate. The ink is scratched on the move from the screen in the text section to the substrate. Due to the effect of viscosity of the ink fixation within a certain range, and make the mark scraper is always in the process of printing and silk screen printing and printing substrates in line contact, the contact line with scraper and movement, due to silk screen printing plate and keep some space between the substrates, makes the screen plate through own tension when printing and reaction of scraper, the reaction is called elastic back. As a result of the impact of the screen printing plate and substrate only mobile line contact, while the other parts of screen printing plate and substrate is out of state. So that the ink and screen fracture motion, to ensure the printing size accuracy and avoid dirty substrate. When the scraper across the entire layout after lifting, while the screen plate also raised, and gently scratch the ink back to the original position. This is a printing process.