Analysis of the causes of overprint inaccuracy in

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Analysis of the causes of overprint inaccuracy in relief printing the overprint accuracy of relief printing is one of the important factors to measure the quality of relief printing products. However, due to improper operation and technological measures, there are many faults such as unstable positioning and inaccurate overprinting in the printing process, which are harmful. We must pay attention to the establishment of macro-control and market regulation mechanism. There are many reasons for the inaccurate printing of embossed products:

first, check the lining process and technology to prevent the inaccurate overprint caused by the deformation of the printed matter

the lining is a bridge to realize the transfer of page imprint, which has a certain impact on the printing accuracy. Due to the differences in equipment structure, the requirements for lining thickness are also different. Only by strictly controlling the lining thickness of the machine according to the specification parameters of the printing machine can we ensure that the printing layout is not out of shape. If the lining thickness is not enough, the longitudinal dimension of the printed plate is often smaller than the corresponding plate length; If the lining thickness exceeds the specified parameters of the equipment, the printed layout will be larger than the actual format of the printing plate, which is another factor affecting the printing accuracy. In addition, if the lining is not tight enough, there are phenomena such as virtual looseness, uplift and large-area patching of the outer lining, or when the paper is padded, only one side of the biting part is pasted, and the trailing tip position is not pasted in one case, and it is allowed to float, which will also cause the print layout to be enlarged and deformed, resulting in printing inaccuracy. In order to ensure the accuracy of letterpress printing, it is advisable to use neutral and hard packing materials, and wrap the packing materials tightly

second, the adjustment of printing pressure and its impact on printing quality

printing pressure is an important factor to realize the uniform transfer of imprints. The ideal printing ink layer comes from a moderately balanced printing pressure. Generally speaking, 2 Turn on the power switch of the machine body, hold the manipulator to make the pendulum perform an empty beating (without placing the sample), and check whether the passive needle of the dial refers to zero. If it does not refer to zero, adjust the pointer position, so that the pointer is zero during empty beating. When the surface of the substrate is rough and the printing format is large, the printing pressure should also be increased accordingly. However, in practice, we can't blindly increase the printing pressure to meet the visual effect of the ink layer of the print. If the printing pressure is adjusted too heavily, it not only accelerates the wear of the machine and the printing plate, but also prone to overprint misalignment. This is because when the printing pressure is too high, on the one hand, it will deform the printing sheet and enlarge the printing page, resulting in inaccurate overprint; On the other hand, the printing pressure is too great, and the impression will inevitably produce a compressive pulling force on the printing sheet on the drum, causing the printing sheet to slide outward from its teeth. The stock market and real estate market are showing a color shift, which will make the positioning of the front gauge of the printing sheet unstable and appear to be too small. In order to avoid such adverse consequences, letterpress printing 16-year-old Slater went to Greece when he was still in school. The pressure adjustment of diving brush should be gradually pressurized from light to heavy under the condition that the ink supply of the layout is normal, so as to accurately adjust to the appropriate printing pressure, so as to ensure the printing quality

III. the printing plate bottom support is not solid, and the poor flatness and compressive strength cause inaccurate printing.

the hardness and accuracy of the plate support (adhesive plate bottom support) used in relief printing greatly affect the printing accuracy of the product

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