Inconsistent printing colors
Since the overprinting is composed of multi-color printing, it is inevitable that the position of the plate roller on each color printing slotting machine is relatively inaccurate, which requires the equipment department to adjust the printing position to ensure that the error is at a minimum. First, since the start of printing has an effect on the thickness of the paperboard, the plate roll of each color should be slightly larger than its previous pressure so that the pressure applied to all colors is equal. Secondly, there are paper feed rollers and traction rollers at the front and the back of each print. The adjustment of these two rollers is very important, especially when the width of the cardboard is too narrow, it should pay attention to adjust the gap and position. In case of partial color registration, two traction belts should be added at the edge of each printing plate to ensure the smoothness of the cardboard during the printing process. Moreover, due to the different degree of warpage of corrugated cardboard, it has an absolute influence on overprinting. If necessary, the cardboard should be replaced again, but it must be flat.
Reason analysis: Inconsistent printing color means that the whole board is unevenly printed along the machine longitudinal or horizontal direction after printing. The main reason for this problem is that the two sides of the horizontal printing are different in color, one side is shallow and one side is deep. There is also an unfavorable cycle of the inking system, insufficient ink flow, and uneven transfer of the transfer roller.
Solution: The uneven lateral color is caused by the difference in the gap between the rubber roller and the anilox roller, the anilox roller and the plate roller. Therefore, to adjust the gap between the three rollers, the two ends must be parallel. Since the printing slotting machine is centered, such as the production of narrower cardboard in the normal period, the rubber roller and the anilox roller will wear faster, and the wear at both ends will be less, and the result after printing will be different if the two ends are colored. Obviously inconsistent, you need to repair or replace a roller. The longitudinal color is uneven because the ink flow rate is too small and the ink supply is insufficient. Therefore, it is necessary to increase the amount of ink, and the machine is idling, so that the amount of ink is fully circulated and then produced, which can reduce the occurrence of such problems.
Corrugating when feeding or printing
Reason analysis: This is caused by two aspects. First, the gap between the paper feed roller (referring to the printing slotting machine) is too small, lower than the thickness of the original paperboard, and the corrugation is crushed before printing; the second is the printing roller during the printing process. The pressure is too large, causing the corrugated part of the printing area to be crushed.
Solution: The gap of the paper feed roller should be determined according to the thickness of the corrugated board, which is basically 0.5mm lower than the thickness of the original paperboard. If the gap is too small, the corrugation is destroyed, and the physical strength of the corrugated box will be affected after the molding; if the gap is too large, the cardboard cannot travel at a constant speed, resulting in inaccurate printing position. Pay attention to adjusting the gap between the printing roller and the embossing roller during printing. At present, most of the corrugated box printing uses a flexographic plate, and the printing method adopts light pressure. The kiss printing is not excessive. If the pressure is too high, the corrugation at the printing site will be crushed and the performance of the carton will be affected. Therefore, the adjustment of the gap between the plate roller and the platen roller is very important, and the printed portion of the handle is not significantly recessed.
Corrugated carton manufacturing process should not destroy corrugated, it is different from the general carton sales package, because the force formed by corrugated is multi-faceted, this corrugation is meaningless once the UV type is destroyed.
In summary, these printing problems are only the most common problems. Others, such as blurred printwriting, distortion, excessive print marks after printing (commonly known as printing and hanging dirty), streaks appearing in stripes, and the ink color does not achieve the desired effect, etc., there are many analysis. However, in addition to objective factors, such as plate material, plate liner, ink, and even the quality of corrugated cardboard, it directly affects the printing effect of corrugated boxes. Therefore, high quality raw materials should be used to ensure the high quality of printing. In order to solve various problems in the printing process, it is also necessary to rely on practical workers with practical experience. First, they must have a certain level of theoretical knowledge. For example, it is necessary to understand the principles and technical procedures of printing equipment and manufacturing processes, and fully grasp the printing system. The relationship between the middle rubber roller, the transfer roller (the anilox roller), the plate roller and the embossing roller, how to skillfully and accurately adjust the corresponding part when a problem occurs, can be quickly solved. Secondly, it is also good at summing up in actual operation. Under what circumstances, which parts are adjusted and the requirements are accurate, this is not easy for general operators. As an excellent driver, you must be good at finding problems and solve problems in time so that productivity can be improved.
All in all, the printing problem can not be separated from the various conditions described above, as long as the printing principle is fully understood, the printing problem will be solved.