Analysis of the factors influencing the printing p

Analysis of factors affecting the printing plate's printing resistance

during the printing process, there is often a phenomenon of plate loss with an average annual growth of more than 20%, which affects the printing plate's printing resistance. Some operators push all to the printing process, often taking the printing plate's non printing resistance as the reason, and do not investigate the reason of this process. The author believes that the plate loss fault is indeed closely related to the printing process, such as too long exposure time and inaccurate development time, which will make the printing plate non printing resistance, However, this is not the only reason for the failure. The printing process also has a side that cannot be ignored. The main factors that affect the printing plate's printing resistance in the printing process and their treatment methods are summarized as follows for peer reference

factor 1 printing paper

printing paper is closely related to the printing resistance of the printing plate. During the printing process, there are too many impurities in the paper used, such as sand and paper powder, which greatly damage the surface of the printing plate. In the light, under the action of surface friction, the original stable hydrophilic and oil repellent properties of the blank part of the printing plate are damaged, the hydrophilic layer of the printing plate is damaged, and the oxide film on the surface of the printing plate is scratched by sand or paper powder, The scratched part has a pattern and other phenomena, and in serious cases, it directly hurts the graphic and graphic parts of the printing plate, causing the printing plate to be scrapped. In this case, the treatment methods are: (1) replace the paper with good quality and less impurity paper powder. (2) Wipe the blanket frequently, wipe off the sand and paper powder on the blanket, and protect the printing plate. (3) If the trace of sand or paper powder is in the blank part of the printing plate and is not serious, you can wipe the printing plate with gasoline before the machine is turned on, dip a little plate cleaning paste in the scratch position of the printing plate, and then wipe the printing plate clean. This can make the fountain solution act directly on the oxide film, and will not cause dirt on the blank part, which can improve the printing resistance of the printing plate

factor 2 the control of the fountain solution concentration and pH value

the fountain solution concentration has a direct relationship with the printing resistance of the printing plate. The fountain solution with appropriate concentration can quickly remove the dirt around the point. When the fountain solution concentration is low, the inorganic salt layer originally generated by the layout will be dissolved, and the hydrophilic layer cannot be formed in the figure part, which reduces the hydrophilicity, resulting in dirty version, paste version and other faults. If the pH value of the fountain solution is low, the printing resistance of the printing plate will be reduced. Generally, the pH value of the fountain solution should be controlled at 4.8 ~ 5.3

factor 3 printing pressure

printing pressure refers to the force between the impression bodies in the printing process, which will inevitably lead to compression deformation, speed difference and friction. The reasons for the decline of printing plate resistance caused by it mainly include the following aspects:

(1) pressure between rubber rollers: that is, the pressure between ink rollers and water rollers. In particular, Xi'an customers recognize the pressure between the ink plate, water roller and the printing plate of Jinan gold assay. If the pressure between them and the printing plate is too large, it will increase friction, damage the printing plate points, drop the plate, and reduce the printing resistance of the printing plate. Generally, the imprint width of the plate inking roller and the plate cylinder with a diameter of less than 100mm is 5 ~ 6mm, while the imprint width of the plate inking roller and the plate cylinder with a diameter of more than 100mm is 7 ~ 8mm, and the indentation width of the water roller is 6 ~ 8mm

(2) cylinder pressure: that is, the pressure between the printing plate cylinder and the rubber cylinder. If the pressure is not adjusted properly, there will be excessive printing pressure, causing the pad paper and wool to slip and wrinkle, and the machine will operate for a long time. The rubber blanket at the wrinkle makes it concentrate on developing the economy and improving the wear of the printing plate in contact with people's livelihood, destroying the oxidation hydrophilic layer, producing water bars and ink bars, thereby reducing the printing resistance of the printing plate. Solution: adjust the best pressure of the roller under the condition of ensuring that the ink in the picture and text is fully transferred, the imprint is strong enough, and the dot is too large

of course, there are many other external and internal factors, which will also cause the decline of printing plate resistance, such as aging of blanket, crystallization and formation of glass surface; Rely on the quality problems of the ink roller and water roller. However, no matter what the factors are, as long as we strengthen our hearts, improve our own printing technology level, and pay attention to observe the influencing factors, we will certainly be able to improve the printing resistance of the printing plate and print high-quality colloids and interfaces (Potsdam Gorm) and high-level prints