Elastohydrodynamic Lubrication Analysis of Ink Layer in Offset Printing

To analyze the features of printing ink in the transfer process, the elastohydrodynamic lubrication theory was used to analyze the maximum pressure and the thickness of the ink in the contact area between a soft ink roller and a hard one. This paper ascertained the viscosity-pressure coefficient of a yellow printing ink by experiment and analyzed the influences of the load, speed and the materials on the pressure and the thickness of the ink in the contact area. Analysis shows that with the increase of the load, the ink pressure increases, the thickness of the ink decreases, and the thickness of the ink tends to be a stable state. When the speed increases, the ink pressure almost does not change, and the ink thickness increases. The change of elastic modulus of the hard roll has slight effect on the ink pressure and the thickness of ink, and the pressure increases with the increase of the elastic modulus in soft roll; however, the change of thickness is not obvious.