Details:
Summary:
In the use of flexographic presses to print over corrugated cardboard, printing plates with thicknesses between 2 and 8 mm are used. Due to its flexible nature, the ink from the plate surface is transferred to the substrate surface in a postprint process.
This same fact, which enables the possibility of printing over a substrate with height differences on its surface (differences due to the tip flute and flute valley areas of the corrugated paper inside the cardboard sheet), makes distortions between the different colors in a print.
Modern flexographic presses with direct drive technology have tools to correct these inaccuracies, but in the corrugated industry’s current machinery fleet, there are many flexographic presses with older technologies, which do not have these tools.
The results of this research reveal the method to minimize these imperfections, working directly in the printing plate manufacturing process by applying different deflation coefficients to the colors of the same set of stereos, depending on the nature and size of each color design.
The obtained results imply considerable time savings in the adjustment of the machine in a job set up time. Also, the reduction of ink consumption and cardboard sheets used during the set up process in a new order. Another consequence in prepress area is the possibility of reducing the trapping between colors in cases where the trapping is increased above necessary due to registration deviations due to the specifications of the machine itself, in order to mask the unequal development between colors.