1、 Dirt on the back of the product caused by improper thickness of printing ink layer

      At present, the judgment of whether the printing ink layer is moderate or not is generally based on visual inspection by experience, which is mainly based on the process of uniform compression of the printing layout, the uniform ink reception of the layout to achieve no bottom exposure, no false printing, and the color phase is consistent with the sample. Situation And Prevention Of Color Printing Products Sticking Dirty

      Due to uneven or insufficient printing pressure, poor glossiness of printing paper, deep hue of original print, weak hue of printing ink and other reasons, insufficient understanding is easy to lead to inaccurate determination of printing ink layer.Situation And Prevention Of Color Printing Products Sticking Dirty

        In this case, if blindly increasing the amount of ink to meet the aesthetic feeling of ink color on the printing page, the back of the product will be sticky and dirty due to too thick ink layer.Situation And Prevention Of Color Printing Products Sticking Dirty

2、 We should correctly understand the relationship between printing pressure and ink layer thickness

       Both theory and process practice clearly show that appropriate pressure is an important condition to realize the uniform transfer of printing ink layer. When the printing pressure is insufficient or uneven, it will inevitably affect the uniform transfer of printing ink layer. Situation And Prevention Of Color Printing Products Sticking Dirty

      The printing process practice can show that when the layout pressure is slightly insufficient or uneven, the ink color of the print layout appears to be blooming, and the thickness of the ink color of the whole layout is not consistent.Situation And Prevention Of Color Printing Products Sticking Dirty

        After increasing the ink output, the ink color of the print appears thick, the phenomenon of layout blooming is eliminated, and the aesthetic feeling of the print layout is also improved. It can be seen that a thicker printing ink layer can make up for the poor contact between the printing ink layer and the substrate caused by insufficient printing pressure and eliminate the printing blooming phenomenon, but it is easy to cause the printing to stick and dirty.Situation And Prevention Of Color Printing Products Sticking Dirty

       On the contrary, if the printing pressure is adjusted enough and evenly, the ink distribution of the layout is appropriately thinned, the printed products will not flower, the ink layer will also appear strong and uniform, and the products will not be sticky and dirty. Therefore, the color printing products should first adjust the printing pressure, then adjust the ink delivery volume, printing effect is better.Situation And Prevention Of Color Printing Products Sticking Dirty

3、 We should deal with the relationship between paper printability and ink layer thickness

       In the process of embossing printing, if there is a lack of correct understanding of the printing suitability of all kinds of paper, the ink distribution is not properly controlled, and it is also very easy to produce printing sticking and dirty phenomenon. Add the paper with poor paper surface smoothness, the ink penetration is fast, and the ink absorption is large.

       When printing this kind of paper, if the layout pressure is insufficient or uneven, it is easy to expose the bottom and bloom after printing. When using the paper to increase the ink supply to make up for it, due to the thick ink layer of the layout and the slow drying speed of the imprint, it is easy to have the disadvantage of printing stickiness. Situation And Prevention Of Color Printing Products Sticking Dirty

      Therefore, for the paper with slightly poor smoothness such as offset paper, the printing pressure should be increased accordingly. Situation And Prevention Of Color Printing Products Sticking Dirty

       The paper with good smoothness, such as coated paper and glass card, can achieve better imprint transfer as long as the appropriate printing pressure. Therefore, the printing ink layer should be as thin as possible to avoid the chance of over printing. Situation And Prevention Of Color Printing Products Sticking Dirty

       At the same time, from the perspective of anti sticking, the process principle of “deep ink thin printing” should be adopted for printing large-area plates, that is, the printing ink hue should be slightly darker to make the printing ink layer thinner, which not only meets the requirements of printing hue, but also achieves the purpose of better anti sticking.Situation And Prevention Of Color Printing Products Sticking Dirty

4、 We should master the relationship between plate properties and printing ink layer thickness

        The practice of letterpress printing process clearly shows that the plate quality has a great relationship with the ink layer printing thickness and printing pressure, that is, if the layout smoothness is poor, the ink layer and pressure required for printing will be large, otherwise it will be small.Situation And Prevention Of Color Printing Products Sticking Dirty

        For example, due to the poor ink affinity and poor smoothness of the printed zinc plate, only by increasing the printing pressure and ink layer thickness can we make up for the defects in the characteristics of the plate and achieve the process effect of full printing ink layer.Situation And Prevention Of Color Printing Products Sticking Dirty

        However, we are very prone to printing dirt, so we should not use color printing products above the open format of the zinc plate printer. Due to the good surface gloss, soft texture, good flatness and ink affinity of resin plate, the printing ink layer can be thinned by one layer, Situation And Prevention Of Color Printing Products Sticking Dirty

     which can achieve satisfactory printing effect and is not easy to get dirty. Therefore, resin plate printing is used for printing a large area, and the anti sticking effect is good.Situation And Prevention Of Color Printing Products Sticking Dirty