The external image of commodities is becoming more and more important in the fierce market competition. Color boxes have become an excellent choice for packaging the external image of commodities because of their high-end, exquisite and beautiful appearance. The color box is not only light weight, easy to carry, a wide range of raw materials, but also has excellent environmental protection. Now let's talk about the influence of ink transfer on printing in color box printing?
The printing process is actually the process of ink transfer. Generally speaking, the ink transfer rate of offset printing is relatively low, about 38%. After the printing plate is inked with the blanket, the ink transfer rate is about 50%, and when the blanket contacts the paper, the ink transfer rate is about 76%. Therefore, it is very important to control the transfer rate of the ink. Ink suitability, ink balance, printing plate, blanket performance, paper, printing machine, etc. will all affect the transfer of ink.
The influence of ink performance on ink transfer
Ink with low viscosity and high fluidity is easy to transfer and has a high transfer rate; ink with high viscosity and low fluidity has a low transfer rate. To increase the ink transfer rate, the viscosity and fluidity of the ink must be controlled. The performance of the ink will also change with environmental changes. When the temperature is high, the viscosity of the ink is lower, and when the temperature is low, the viscosity of the ink is higher. In actual production, inks of different models, types and different drying methods should be selected according to the actual situation. In addition, adding an appropriate amount of varnish to the ink can adjust the performance of the ink, which is conducive to controlling the increase in dots and improving the ink transfer rate.
The effect of blanket performance on ink transfer
The blanket must have good ink absorption and ink transfer properties, as well as oil resistance, acid resistance, alkali resistance, and good elasticity. If the blanket is not cleaned thoroughly after printing, the ink retained in the fluff will slowly harden the conjunctiva, which will damage the fluff-like structure of the rubber surface, which directly affects the ink acceptance rate of the blanket, thereby reducing the ink transfer rate of the blanket. Therefore, after printing, the blanket should be washed thoroughly. If the downtime is relatively long, a layer of pumice powder can be rubbed on the surface of the blanket to keep the original fluffy structure on the surface of the blanket and to ensure that the blanket has good ink absorption and ink transfer.
In addition, printing pressure refers to the interaction force between the printing plate cylinder and the blanket cylinder, and between the blanket cylinder and the impression cylinder. It is a necessary condition for ink transfer.