Analysis and elimination of the paste failure of t

Analysis and elimination of the problem of printing negative text pasting

1. After the phenomenon of negative text pasting occurs, first check whether there is a problem with the printing plate

in addition to the original version factors, the reasons for paste in plate making:

① in terms of PS version manufacturing quality:

first, the PS version is too shallow, too thin, and has little water storage

second, some PS plates do not have enough time to seal the holes, and the extremely small holes in the plate are not sealed, which makes the absorption capacity of the plate too large

third, the sand mesh and river sensing layer of the regenerated PS plate are uneven. When printing with the above PS plate, because the negative text is hydrophilic, the water storage capacity is poor, and it is easy to pollute, it can't resist the spreading of the ink film on the ground, resulting in a paste plate

② printing:

first, the exposure time is not enough or the developer concentration is low; The combination of plastics and bicycles -- the cooperation between the two industry giants

second, due to the neglect of indoor light in the printing process, the PS version produces fog under natural light, which makes it difficult to develop, resulting in the fat sensitivity of the negative text part, the poor lipophilicity of the field and the graphic part, and the machine printing, the ink absorption performance of the field part is weakened. In order to achieve the thickness of the ink film, it is necessary to increase the amount of ink in the ink bucket, which is more likely to cause the negative text paste

solution:

first, use PS plate with high quality standardization to dry the printing plate

second, the exposure should be sufficient and the development should be thorough during the printing operation

third, indoor lighting in the printing process should not use light sources with strong light, windows should be covered with ink cloth, and doors should be double doors with ribbon spacing

2. In addition to plate making factors, the main reason is that the ink film is too thick during printing.

because the surface smoothness of color printing parts is high and the absorption is not strong, the ink film is a little thick, it is easy to spread into the Yin text, resulting in paste failure

there are two cases of ink film thickness:

first, the ink film thickness caused by small water and large ink volume is too thick. After official printing, it is found that the ink film thickness is too thick, increase the amount of water, and then slightly adjust the amount of ink

second, the ink film is too thick due to large water and ink. This is because the amount of ink in the ink bucket is adjusted too much before formal printing, and the water supply is wrongly increased after continuous printing, or when printing starts, the water is large, the ink film is thinner, and the amount of ink is wrongly increased, resulting in a vicious cycle of large water and ink, serious ink emulsification, reduced viscosity, and easy to paste

solution:

① in daily operation, we should often sum up experience and improve the technical level. Before the official printing, we should calculate the ink amount correctly. It is better to lower the ink amount rather than too much. If we have insufficient experience, we can ensure the safe ink absorption paper debugging to achieve the appropriate thickness of the ink film and prevent the paste

② since the water supply of the field layout cannot be small, in order to avoid the ink film thickness caused by large water and ink, you can reduce the pH value of the liquid medicine (increase the acid value) or add an appropriate amount of surfactant to reduce the water supply. If there is a large amount of water and ink and ink emulsification, the emulsified ink on the ink cleaning roller should be cleaned in time, and then reduce the amount of ink, and re ink printing

③ when mixing ink, the color of multicolor and light color ink prints should be slightly darker than the original. The ink with strong coloring power should also be selected for the three primary colors. The measures of deep ink thin printing can also avoid the ink film being too thick

3. In addition to the above two main reasons, the following factors will also cause negative text paste during printing:

① the printing pressure is too high, mainly because the printing pressure is too high

② the fluidity of ink is too large; Yicheng Xinneng also established a special subsidiary Henan Yicheng Hanbo Energy Technology Co., Ltd. (hereinafter referred to as Yicheng Hanbo) to be responsible for the above 10000 ton cathode material project

③ poor water resistance of ink particle group or pigment

④ excessive amount of dry oil during inking

⑤ aging of inking roller

⑥ the inking roller is too soft and bent, and there is relative slip with the plate cylinder during operation

⑦ excessive pressure between inking roller and printing plate

⑧ the water content of the layout is too small or the water roller is too dirty, and the pressure between the water roller and the printing plate is too light or too heavy

⑨ the rubber blanket is not tight

⑩ the drum lining is not appropriate

⑾ the pH value of paper is greater than 7 (alkaline), which is easy to dilute the concentration of liquid medicine

⒁ serious paper degumming

⒀ in summer, due to the rapid drying up of moisture in the PS version, the layout is not coated with protective glue when it is stopped, and reopening printing will cause and ensure the accuracy of the paste