Printed sign products that use metal plates, sheets, nickel sticker and other materials as substrates are called metal sign printing. In the process of metal sign printing, it is often encountered that there is a color difference in the printed matter.
The following is a brief introduction to the control methods of chromatic aberration in the process of metal sticker printing:
1. Dot deformation and chromatic aberration: The main reasons for the occurrence of dot deformation and chromatic aberration are:
(1) The increase or decrease of mechanical dots, including the influence of printing pressure, ink, fountain solution, blanket, metal plate surface coating, etc.;
(2) The increase or reduction of optical dots refers to the change of dots in the process of transferring the metal sign printing negative to the PS version.
Control method:
(1) Adjust the pressure to meet the printing requirements. If the pressure is too large, the metal sticker printing plate will show expansion of graphics and text, and when the dot imprint level is unclear and severe, it will cause the plate to drop, which will affect the printing durability. If the pressure is too small, the printing plate has poor inking, poor imprint clarity, and empty dots;
(2) Control the viscosity of the ink;
(3) Control the pH value and conductivity value of the fountain solution;
(4) The blanket device conforms to the standard to avoid the dot change caused by stretching, torsion or compression deformation of the blanket;
(5) Precisely control the exposure time to ensure the recovery of the negative.
2. The main reason for the color difference caused by the overprinting prohibition is that the positioning of the color plates in the overprinting process is strictly prohibited.
Control method:
(1) The pressure adjustment meets the requirements of metal sticker printing, including various pads;
(2) Precise positioning of front gauge, side gauge and gripper;
(3) The device PS version conforms to the regulations;
(4) The scale of the print is restored to the scale of the film;
(5) Accurate positioning between each color version;
(6) The manufacturing scale accuracy of metal stickers conforms to national standards and equipment functions.
