The manufacturing accuracy of the plate roller mainly refers to the coaxiality of the plate roller, the inner roundness of the plate roller, and the taper dimension accuracy of the cone hole of the plate roller should be higher, especially the influence of the circular runout of the plate roller on the overprint error is more critical. If the circular runout error of the cylinder is large, it will lead to the irregular change of the tension of the aluminum foil substrate in the overprint, and change the length of the whole printing path in varying degrees, resulting in inaccurate overprint.
The installation accuracy of the printing plate roller is mainly affected by the axial installation of the plate roller on the plate roller shaft before printing. When installing the plate roller, it is necessary to ensure that the taper holes at both ends of the printing plate cylinder and the cone head of the fixed plate are clean, and ink or other impurities cannot adhere on both ends of the cone head, otherwise, the assembly accuracy of the plate and the shaft and the overprint accuracy will be affected, Generally, the order of installing the printing plate is to first install the plate and the round plugs on both sides and lock them with the plate shaft. The concentricity of the plate, the plug, and the plate shaft are better. The positioning key should be installed and the assembly should be tight. After the assembly, the radial runout of the printing plate should be controlled within 0.1 mm. The indexing table and the radial runout meter can be used to detect whether the plate roller has excessive radial runout. It should also be noted that the printing plate should be loaded into different printing stations according to the given color sequence during plate making. The rotation direction of the printing plate should be consistent with the direction of the regular line arrow in the color code. The color code of the first color plate roller should be transmitted in front of other overprint color codes, and the wrong direction should not be installed.
Influence of guide roller of printing machine: aluminum foil multi-color overprint machine uses more guide rollers to position and transport aluminum foil, which ensures the normal operation of aluminum foil in the printing process and provides conveying tension. If the axial and radial movement accuracy of the guide roller is poor, it will lead to the irregular change of the aluminum foil substrate tension and inaccurate printing overprint. This is because the printing machine runs for a long time. Due to the influence of the machine itself and external factors, the screw of the guide roller is loose and the bearing is damaged, and the running resistance of the guide roller changes, The length of the printing path of the guide roller between the units changes, which causes the change of the tension of the aluminum foil substrate, thus affecting the accuracy of the printing register.
Influence of printing ink color and viscosity: the color of printing ink will be used in the gravure system of soft composite materials such as aluminum foil film. Printing coater will affect the sensitivity of the scanning tracker of the automatic registration system. Due to the different colors of the multi-color mark during overprint, the intensity of the reflected light received by the photoelectric scanner is different, and the height of the corresponding pulse value is also different. The pulse peak value is larger when the black ink is deep, and smaller when the black ink is light. Ink also needs to ensure a certain viscosity, not too thin, in order to avoid printing overprint color code easy to "tail". The angle of the scraper should be correct, the pressure of the scraper should be moderate, and the printing line should be wireless. The dot depth of the color code should be clear and full.