What caused the misprinting of relief printing?

The overprint accuracy of letterpress prints is one of the important factors in measuring the quality of letterpress products. However, due to improper operation and process measures, there is no lack of faults such as unstable positioning, overprinting, and misalignment during the printing process. The hazards are serious and must be taken seriously. The reasons for the inaccurate printing of embossed products are many:

First, the good lining process technology to prevent the printing product deformation caused by overprinting is not allowed

Lining is a bridge that realizes transfer of layout printing and has a certain influence on printing accuracy. Due to the differences in equipment structure, the requirements for the thickness of the lining are also different. Only by strictly controlling the lining thickness of the machine according to the specification parameters of the printer, can we ensure that the printing plate surface is not deformed. If the thickness of the lining is not enough, the longitudinal dimension of the printed layout is often smaller than the corresponding length of the printing plate; if the lining thickness exceeds the equipment specified parameters, the printed surface is larger than the actual size of the printing plate, which is another factor that affects the printing accuracy. In addition, if the lining is not tight enough, there are phenomena such as looseness, bulging, and large areas of the outer lining, etc., or only the side of the occlusal part is stuck on the upper pad, and one example of the tip is not affixed and allowed to flutter. , This will also cause the printing plate layout to be distorted, resulting in print misalignment. In order to ensure the accuracy of letterpress printing, it is better to use a neutral, harder packing material and to pack the packing material tightly.

Second, the adjustment of printing pressure, the impact on the printing quality

Printing pressure is an important factor in the uniform transfer of prints. The ideal printing ink layer is derived from moderately balanced printing pressure. In general, when the surface of the substrate is rough and the printing surface is large, the printing pressure should be increased accordingly. However, in actual operation, the printing pressure cannot be increased blindly to satisfy the visual effect of the printed ink layer. The printing pressure is too heavy, which not only speeds up the wear of the machine and printing plate, but also causes overprinting misalignment. This is because when the printing pressure is too high, on the one hand, the printed sheets may be deformed, causing the printed sheets to be enlarged, resulting in inaccurate overprinting; on the other hand, the printing pressure is too high, and the imprints on the rollers are bound to be oppressed during the imprinting. Sexual pull force causes the slippage of the printed sheet to slide outwards from the gripper teeth, which will make the prescribed position before the printed sheet unstable and appear to be too small. In order to avoid this undesirable effect, the pressure adjustment of letterpress printing should be gradually light and heavy under the condition that the page ink supply is normal, so as to accurately adjust the printing pressure to ensure the printing quality.

Third, the printing plate base is not solid, flatness, poor compressive strength caused by printing is not allowed

The hardness and precision of the plate support used in letterpress printing (viscous platen) largely affect the printing accuracy of the product.