Study On The Controllability Of Prepress Quality Based On Dot Enlargement During Flexographic Printing

During flexographic printing,the enlargement of dots has a serious impact on the quality of printed products.Consequently,it is really necessary to study the controllability of pre-press quality based on this situation.Hence,we can reduce the dot enlargement rate and improve the quality of printed products.In this paper,according to a series of experiments,I adopt the prepress test and pre-compensation method to study the influence rule among the printing pressure,the dot diameter,the number of screen lines(distance between the dots)and the height of the relief on the dot enlargement rate.In the meantime,I do the research about the relationship between the four factors and the actual printed area.The main contents of the thesis are:The printing plate was designed and produced according to the research factors.The plate content is divided into the regular part(according to the percentage of the dot and the number of screen lines designed)and the custom(according to the diameter of the dot and the distance between the dots designed).Printing was performed under ten printing pressures,and the obtained samples were subjected to data measurement and processing.Through the analysis of the regular printing samples,I found the influence of printing pressure,number of screen lines and relief height on the dot enlargement rate.The research results show that the greater of the printing pressure,the larger of the screen lines numbers,the more serious for the dot expansion,and the degree of influence of the two on the dot enlargement rate is different.When the percentage of dots is between 20%and 80%,the dot expansion is severe;when the dot percentage is less than 20%or greater than 80%,the dot enlargement is lighter.Comparing the expansion ratios of the three relief heights(0.5mm,0.6mm,0.7mm),the relief height has less influence on the dot expansion,and the dot expansion rate at 0.5mm is the smallest.At the same time,under the conventional part,when the percentage of dots is 20%80%,the influence of printing pressure,number of screen lines and relief height on density and hue angle is explored.Through the analysis of the custom part,the influence of printing pressure,embossing height,distance between the dots and the diameter of the dot on the actual printing area is explored.I obtained the printing pressure,the distance between dots,the diameter of the dot,and a mathematical relationship model on the actual printed area within a certain range.At the same time,based on the research results of variable factors on the influence of dot expansion,a new pre-compensation method is proposed,which has certain guiding significance for the selection of flexographic printing parameters.