The Research Of Parameters And Quality Evaluation For Gravure-offset

Because the low cost, high production efficiency and the more used substrate, thegravure-offset has obtained much attention in the printing area. The quality of printing can bereflected by three exterior features: whether the edges of lines are straight or not; the thicknessof line; the surface roughness of line. The first feature is controlled by dot shape and press;and the other features are controlled by the transfer rate and the number of satellite droplets.In order to explain the effect of viscosity and speed on the satellite droplets, Maxwellviscoelastic model has been used in this paper. Separation speedV and viscosity is closelyrelative to the number of satellite droplets; when the speedV and viscosity are0.1m/s，0.25Pa s, respective, there are four relatively concentrated satellite droplets; When thespeedV and viscosity are small, there are a few satellite droplets, one bigger drop of them;when the speedV and viscosity are large, there are much dispersive satellite droplets.From adhesion energy point, the effect of contact angle on transfer rate of ink has beenanalyzed. In order to obtain high transfer rate, the contact angle between ink and upper plate(printed material) should be small; and the angle between ink and lower plate should belarge. When the contact angle is small, the adhesion energy is large.The effect of gravure angle and space ratio of gravure R on the transfer rate of inks isnonlinear. When gravure angle45,the factor of transfer rate f (T)1.0,and it hasnothing with the space ratio of gravure R.When the gravure angle [3060], the f(T)can acquire the maximum. If space ratio of gravure R [0.21.2], both the transfer rate andtransfer volumes are appropriate.In this paper, the main factors influenced the thickness of printed picture have beenfound by the ANVOA of the statistics. The factors, the volume of ink(C), viscosity (B),printed speed (A), viscosity*volume (BC), have important influence on thickness.