Pay attention to the change of equipment adjustmen

Pay attention to the change of equipment adjustment accuracy during printing

in the process of direct reading digital quantitative printing, the main components of the printing machine, such as printing plate cylinder, embossing cylinder, embossing roller, inking roller and various transmission gears, may change their own accuracy and adjustment accuracy due to the influence of various factors, thus affecting the printing quality. In the printing process, they should carefully check, find problems and solve them in time

(1) there are three possible problems with the printing plate cylinder and the embossing cylinder. One is the concentricity of the cylinder body and the supporting journal. The concentricity of the printing plate cylinder and the embossing cylinder must be good. When the printing machine operates normally, the vibration error should not exceed 0.01mm, otherwise the pressure at the point is not easy to adjust. If the pressure is heavy, the idea will expand. If the pressure is light, the current P/b of the non-ferrous metal industry is 2.16. Some images can be printed, and some cannot be printed

second, if the parallelism between the two rollers changes, the printing pressure changes. If the two rollers are not parallel, and the gap at one end is large, the printing pressure becomes smaller, the ink transfer is small, and the printing ink is insufficient; The gap at the other end is small, the printing pressure becomes larger, and the ink transfer volume is large, which makes the printing ink heavy and easy to form the defect of heavy ink at one end and light ink at the other end in the same printing surface

third, if the gap between the two rollers changes, the printing pressure will change. 1. Confirm the safety and pressure resistance of the carton, the code quality index standard. The gap between the two rollers is large, the pressure is small, the amount of ink transfer is small, and the printing ink is light. On the contrary, the printing ink is thick

(2) the possible problems of the corrugation roller include the accuracy change of the corrugation roller itself and the position accuracy change between the corrugation roller and the plate cylinder and the inking roller

the accuracy change of the wrinkle roll. The accuracy of the corrugation roller mainly includes the depth of the hole, the number of lines and the surface finish

wrinkle roll hole depth: the depth of engraving on the upper line of the wrinkle roll will directly affect the output of ink volume. If the line carving is deep, the amount of ink output is large. The ink layer of printed products is thick and deep, and the color is bright. However, attention must be paid to the drying of the ink layer. Excessive thickness of the ink layer will make the ink on the print difficult to dry, and it is very easy to form a situation that the outside is dry but the inner layer is not dry, resulting in ink sticking to the product; On the contrary, if the line engraving is shallow, the ink volume of the difficult printing plate on the embossing roller is less, and the printed products lack a certain amount of ink, resulting in poor color

at present, the depth of the engraving of the roller hole is generally between 22 and 30. According to different properties of substrates and products, the corresponding line depth is adopted. If the ink viscosity, particle size and other factors or the surface wear of the roller are affected, changing the depth of the roller will reduce the ink delivery to the printing plate and directly affect the quality of the printed matter

roller finish: the roller engraving has a good finish, the ink transfer is uniform and delicate, and the formed dot shape is good. It is especially obvious in flat line printing, otherwise it will make the ink uneven, the restoration of dot type tone level formed after dot printing is not ideal, and the clarity is also damaged

number of wrinkle roll lines; The number of eyelets on the embossing roller is very important for the printing line products. It is generally configured according to the quality requirements of the printed matter. If the number of threads on the embossing roller does not match the quality requirements of the printed matter during the printing process, it should be replaced in time

the change of the relative position of the embossing roller, the plate cylinder and the inking roller, including the change of parallelism and the change of the gap between them. These changes will change the ink transfer performance of the roller and affect the quality of the printed matter

(3) the possible problems of the inking roller are the loss of surface quality and the change of position accuracy with the wrinkle roller

the surface quality of the inking roller is damaged. If there are grinding lines or scratches on the surface of the inking roller, the uneven ink transfer will make the color uneven when printing products. Flat lines are more visible. Therefore, the surface of the inking roller must not have abraded lines or scratches. If found, it should be replaced in time

the position between the upper ink roller and the wrinkle roller changes, mainly referring to the parallelism and the size of the gap between them. These changes directly affect the changes of ink transfer performance, and special attention should be paid to inspection

(4) the accuracy of the transmission gear changes, and the gear accuracy is the basis to ensure the concentricity of each roll

the gear accuracy of each roll is not good, which will produce mechanical defects such as micro vibration, which will bring certain difficulties to line printing, so that the whole line printing cannot obtain an ideal printing pressure

at the same time, if the gear transmission surface is not clean and dirty, it will also affect its transmission accuracy

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