1. Printing color difference caused by pressure discomfort
Printing pressure is one of the conditions for ink transfer, because the printing plate surface can not be absolutely flat, the surface of the paper is inevitably subtle concavity and uneven thickness, if the printing pressure is insufficient or uneven, printing ink layer is prone to uneven thickness. The ideal printing process is on the basis of the "three flat", that is, the requirements of the printing layout and substrate and lining surface are relatively flat conditions, so that the printing on the more uniform ink. When the printing pressure is insufficient or uneven, the lining body and the printing layout have bad contact, then need to increase the amount of ink, to meet the layout of the ink visual effect, but this will not only increase the consumption of ink, and easy to produce printing color difference and printing quality problems.
2. Printing color difference caused by poor ink roller
Lithography, letterpress printing process, printing products can obtain uniform ink, the quality of cots has a crucial role. Color printing on the machine, generally equipped with rollers, rollers and rollers, which have a greater impact on the ink thickness is the transfer of cots and rollers. And how the elasticity, viscosity, roundness, hardness and surface finish of the roller, to a large extent determines the quality of printing ink. If there are such conditions as poor elasticity, insufficient viscosity, roll eccentricity, colloid hardness and colloid finish of the inking roller, it is easy to cause inking uneven or unstable phenomenon in the printing process, so that the printing ink color of each sheet is not consistent. Therefore, printing color products should use a better quality cots, in order to ensure that each printing cycle coating on the layout of the ink to keep basically the same.
3. Printing color difference caused by poor ink setting
When the ink fountain roller iron circle degrees of poor or the presence of wear deformation, ink fountain steel plate also wear deformation, and control the ink fountain roller rotation institutional flaws, make the amount lost in the process of printing ink is not stable, can also cause the production of printing color, ink will comprehensively increase or reduce throughput, there are two kinds of control mode, one is by adjusting the ink fountain sheet steel and ink (ink) iron roller clearance to implement; The second is by adjusting the size of the rotation of the iron rod to achieve.
