Analysis of reasons: Overprinting problems are common in the printing industry. Because it is a multi-factorial component, it is not easy to solve problems. First of all, the accuracy of position and accuracy of the multi-color printing slot machine itself is a direct factor. Followed by the adjustment of the feed roller, pull roller, the use of traction belt, the accuracy of the layout of the printing plate, and the problem of warpage of the cardboard will produce the problem of overprinting.
Solution: Since overprinting is composed of multi-color printing, it is inevitable that the position of the printing roller on the various printing slot machines is relatively inaccurate. This requires the equipment department to adjust the printing position to ensure that the error is at the minimum limit. First of all, since the initial printing has an effect on the thickness of the board, the roll portion of each color should be slightly larger than the previous one so that the pressure exerted on all the colors is equal. Secondly, there are feed rollers and draw rollers at the front and rear of each printing. The adjustment of these two rollers is very important, especially when the width of the paperboard is too narrow, attention should be paid to adjusting the gap and position. In case of local color registration, two traction belts should be added at the edge of each printing plate to ensure that the cardboard is steadily over-printed. Furthermore, due to the different degree of warpage of corrugated cardboard, it has absolute influence on overprinting. If necessary, cardboard should be replaced again, but it must be flat.