Reasonable control of corrugated flexographic printing pressure (below)

The pressure between the plate cylinder and the impression cylinder

In general, the contact pressure between the plate cylinder and the impression cylinder is also light, but in the actual printing process, since the corrugated cardboard is not as smooth as the ordinary paper, it is difficult to achieve this in printing. However, it is also necessary to strictly control the pressure and try to do light pressure. The distance between the plate cylinder and the impression cylinder is the total thickness of the plate plus the thickness of the corrugated cardboard. The total thickness of the plate can be controlled, but the thickness of the corrugated cardboard is difficult to control. The printing quality of corrugated cardboard is closely related to the thickness error and flatness of corrugated cardboard itself. Among the printed materials, corrugated paper is the worst, not only the thickness of a piece of cardboard is very different, and the thickness and corrugation level error of the same paperboard is also relatively large. When printing, it is required to meet the thickness requirements of all corrugated cardboard and achieve good The quality control is very difficult.

As for the control of the gap between the plate cylinder and the impression cylinder, according to practical experience, it is necessary to achieve the following requirements:

Gap = total thickness of printing plate + thickness of corrugated board - error amount of corrugated board thickness (usually 0.5mm) - error amount of roller and plate (usually 0.1mm)

The feeler and gauge are used to control the gap between the plate cylinder and the impression cylinder. Within this control range, it is already possible to ensure that the inked portion of the corrugated paper is completely printed out. However, due to the thickness error of corrugated paper, when printing thick corrugated cardboard, the large amount of compression of the printing plate is not conducive to improving the printing quality. Therefore, to ensure the printing quality, the quality of the corrugated cardboard should be improved as much as possible to reduce the thickness error. If you do not control the operation, the pressure will be too serious hard-mouthed, on the ground inconsistent, ink ink part of the line is shallow, non-ink-edge hard mouth and ink is darker. The excessive pressure on the printed cable version will cause the network to enlarge the paste, and 30% to 40% of the outlets have hollow spots.

To ensure the printing quality of corrugated paper, it is necessary to reasonably control the pressures of the above three aspects. During the trial printing and printing of the school, if there is a phenomenon that partial printing is not possible, generally do not take measures to increase the pressure, because although this can temporarily solve the problem of partial printing, it will make most of the rest of the imprinting. Deformation is not worth the candle. The correct approach should be to use the pad version of the method to solve, that is, in accordance with the actual situation in the pad after the film pad method, because the corrugated board printing is generally printed on the plate attached to the film, so use pad method Still more convenient. In addition, the printing plate lining technique can also be used. For example, today's ideal air cushion type lining technology, practice has proved that it can effectively reduce the printing surface pressure, control the dot expansion, to avoid deformation of the printing plate, a good compensation effect for the oversized plate roller, for low quality Corrugated board printing also has good printability, and compared to thicker printing plates, the use of air cushions can also reduce the cost of nearly 1/3. Therefore, it is a method worth promoting.