The screentone product is the object worthy of attention in the quality control of color printing process. It is a crucial link to print high quality fine mesh products and technical control of production process.
1. Choose the packing liner with an appropriate hardness to make the dot print clear and clean.
Whether it is a screen adjustment product of the printing process or a flat printing process, the soft and hard degree of the pad is an important factor to determine the printing effect of the dot. If the pad is too soft, dot printing is easy to deform and expand. To make the dot print clear and smooth, the neutral and hard pad should be used. Insulating paper, paper jam, kraft paper, sheet base, and so on belong to the hard pad. But cloth, fine cloth, newspaper belong to the soft lining, easy to deform after pressure.
2. Adjust the appropriate printing pressure.
The printing dot products of the relief and plate process need to be transferred by pressure. If the pressure is too large, it is easy to make the dot expand and deform, even accelerate the wear degree of the plate. If the pressure is too small, the dot reproduction effect is poor, the dot is easy to blur, and the print image layer is poor. The printing pressure should be in a relatively parallel state with uniform and moderate contact between the rollers and the plates (convex plates).
3. Adjust the contact pressure of the ink roller to the plate, and select the soft and hard suitable rubber roller.
The ink roller is the main carrier of ink transmission, adjusting the appropriate contact pressure of the printing plate, and plays an important role in the quality of dot printing. The pressure of the ink roller is too large, which makes the layout dot wear and deformation easily, and it is easy to produce a pasted plate. The pressure of the ink roller is too small, which will easily cause uneven and insufficient ink on the layout, and make the printing point unclear.
4. Choose ink with high fineness for printing.
If the ink printing dot with low fineness is adopted, the printing dot is easy to hair due to the coarse ink pigment particles, and the printing plate resistance is also low. Ink fineness is low also easy to produce paste version defects. Therefore, printing dot products should be selected with high fineness ink for printing. High fineness of ink, its concentration is large, can make printing dot clear, full.
5. Pay attention to adjust the viscosity and fluidity of ink.
The ink viscosity is large, which is easy to cause uneven ink transmission, dot roughing, printing plate, paste plate, and other phenomena; if the ink viscosity is small, it is easy to emulsify the ink and make the layout appear dirty and other adverse conditions. The fluidity of ink is closely related to viscosity. For ink with high viscosity, its fluidity is relatively small. On the contrary, liquidity is large. The ink flow is too small, which is easy to cause the coating is not smooth and uneven so that the reproduction effect of printing dot is poor; ink with too large fluidity is easy to make dot printing under full and poor clarity. Therefore, if the viscosity and fluidity of ink are not suitable, additives and ink oil can be used to adjust.
6. Pay attention to selecting the right paper for printing fine mesh products.
How smooth the paper is, directly determines the printing quality of the dot. If the paper smoothness is poor, it can not make the dot accurately restore. Because of the paper concave and so small dot printing, so that the printing level effect is not good. Therefore, the printing mesh adjustment products should pay attention to the choice of smooth paper to ensure the true reproduction of the original. Generally speaking, the smoothness of paper or board such as copperplate paper, glass card is better, and the quality of daily printing fine screen products is better.
7. Pay attention to the maintenance of equipment to prevent printing distortion.
The accuracy of the equipment determines the printing quality of the product. If the equipment precision is poor, the increased value of the printing dot will be large, and the product quality will be bad. Therefore, at ordinary times, we should pay attention to the maintenance of equipment and do a good job in lubrication of key parts, such as roller gear, shaft head, and linkage press device to keep a good lubrication state, to prevent the imprinting expansion, flower or shadow caused by wear and loosening of parts, and make the printing point deformed.
8. Attention should be paid to control the appropriate printing speed to improve the accuracy of the set.
The speed adjustment range of automatic printing machines is large. If super high-speed printing fine screen printing is adopted, it is easy to produce unstable and inaccurate overprint. If the appropriate printing speed is adopted, the error of registration caused by paper factors and machine discomfort can be reduced and reduced. The proper speed can keep the paper conveying and handover relatively stable, and ensure the quality of the printed products.
9. According to the color number of the printed products, the printing type should be selected reasonably to ensure the quality of the printed products.
The practice shows that choosing the appropriate printer according to the characteristics of the printing parts is an important way to improve the quality of the products. The fine mesh adjustment products of multicolor overprint should be printed by multi-color machines as much as possible to improve the quality of the products.
In conclusion, as long as we pay attention to the process and technical links in the production process, and take appropriate technical measures according to the characteristics of the products, it can not only improve the printing quality of the products but also effectively prevent and avoid the occurrence of various defects and improve the production efficiency.