Several major factors affecting the decline of printing plate wear and printing resistance
the nonstandard printing process will cause the insufficient printing resistance of the printing plate. In the process of printing workers to detect the physical properties of various building reinforcement bending in the forward and reverse directions, they will be affected by many factors, which will damage the printing plate and reduce its printing resistance:
1. Printing pressure: printing pressure refers to the mutual force between imprints in the printing process, This will inevitably lead to compression deformation, velocity difference and friction, and destroy the original structure and adsorption performance of the layout. The first is the pressure of the cylinder, that is, the pressure between the plate cylinder and the rubber cylinder, which won the laureate of the excellent enterprise award. If the pressure is too large, it will aggravate the friction between the printing plate and the rubber, and the sand on the surface of the printing plate will gradually wear out, so that the points of the graphic part of the printing plate will be damaged, resulting in the decrease of the printing resistance of the printing plate. Thirdly, the pressure between the ink rollers, that is, the pressure between the ink roller and the water roller, especially the pressure between the ink roller against the plate and the water roller against the plate and the printing plate. If the pressure between them and the printing plate is too large, the friction will be increased, so that the points of the printing plate will be damaged, resulting in "plate loss"
2. fountain solution: the purpose of fountain solution is to maintain the balance between the blank part and the graphic part, protect the blank part of the printing plate from being invaded by ink, and prevent it from expanding to the graphic part. In printing, when the ink film of the printing plate is 3pm, the water film is 1lam, which completely prevents the expansion of the ink on the blank part. If the amount of printing plate fountain solution is too large, ink emulsification is easy to occur, the color density of imprinted ink cannot meet the requirements, and the corrosion of printing plate base is deepened; Printing plate "paste plate" and "pile ink", which affect the quality of printing products
3. The surface of the substrate is rough, powdered, roughened, and there is sand in the paper. These substances will increase the pressure during the printing process, accelerate the wear of the graphic part of the printing plate, and reduce the printing resistance of the printing plate
4. Some inks have coarse pigment particles, such as gold silver powder ink and white ink. In the process of ink transmission, it will increase the friction coefficient between the printing plate and the blanket, accelerate the wear of the image and text part, and produce "pattern"
the operator 1 must pay attention to the cleaning of the fatigue testing machine. 5. Keep enough residual ink layer in the image and text part of the printing plate to prevent the image and text from directly contacting with the fountain solution and protect the image and text part of the printing plate. If the remaining ink layer in the image and text part is insufficient for a long time, the photosensitive layer will be directly worn or corroded by acid and alkali, which is easy to cause "stencil" phenomenon and greatly reduce the printing resistance of the printing plate
6. Influence of printing machinery and equipment failure on printing resistance: part of the reason is closely related to the improper operation of the equipment. For example, due to the improper installation of the machine, the printing speed is too fast, and the printing pressure is too high, which causes the vibration of the machine for measuring the other tensile properties of chopped glass fiber reinforced plastics, and the wear of the printing plate will be accelerated during printing. The shaft sleeves at both ends of the rubber drum are seriously worn, causing the rubber drum to jump during printing, which will inevitably cause the wear of the printing plate and reduce its service life
7. the rubber blanket is aged for a long time, the rubber hardens and loses elasticity, the grease sensing ability decreases, the ink transfer performance is poor, and the ink on the printed matter is light, which accelerates the wear of the printing plate