Printing a four color experience with a monochrome machine

With the use of a single-color offset press to print four colors, there are many variable factors and strong technicalities in printing. The following are some of the experiences and experiences accumulated when I used the monochrome machine to print four colors.

1. Before printing, carefully check whether the quality of the printing plate is acceptable, and repair the excess dirty spots and lines on the plate.

2. Before starting the machine, carefully adjust the feeder, paper feeding roller, side pull gauge, and the transfer time of each part, so that the machine can run smoothly, pull the paper in place, and the paper is accurate at the time of handing over the parts. Then adjust the roller pressure, use the way to go through the printing plate to adjust the amount of ink required for printing.

3. The color order is yellow, magenta, cyan, and black. Whether it is from the transparency of the ink or viscosity analysis, this color sequence arrangement is more scientific. Putting yellow on the first color, the slight beating of the rules has little effect on the overall printing effect. When printing yellow ink, you can also better observe and adjust the machine to facilitate accurate overprinting of the last three colors. However, the color sequence of monochrome machines is not static and should be based on the characteristics of printed materials and manuscripts. For example, when a paper with easy-to-powder and contaminants on the surface is used, a smaller color should be printed on the front surface so that after the two colors are printed, the paper powder and impurities are almost completely lost. Smooth, no dirt, the overall effect of printed products is good.

4. Before printing, the viscosity, fluidity, drying time and paper quality of the ink are carefully analyzed. Adding additives in the ink is beneficial to the improvement of the quality of the printed product.

5. After the machine has properly adjusted the amount of paper and ink, it is necessary to agitate the ink fountains frequently, add ground and ink, and maintain a certain amount of ink in the fountain to ensure normal supply of ink. To observe the water in the layout, use the least amount of water under the premise of not compromising the plate, so that the ink is balanced and the ink is uniform, and avoid paper stretching due to water, so as to facilitate accurate overprinting. Observe the printed sheets diligently and carefully compare the proofs to ensure that the printed inks are the same. Always check the overprinting situation so that the machine can be adjusted in time to make the overprinting of the printed product accurate. When printing the first color, use the kerfs to see the accuracy of the rules. In addition, we must pay attention to whether or not the printed products are sticky or back-printed. If any, we must adopt measures such as the use of multi-compartment laminates, diligent access to printed sheets, and dusting (spraying powder should be used in the last color). Each time you reboot, you must use the method of passing through the offset paper to ensure that the ink is consistent.

The use of a monochrome machine to print four-color prints, the shorter the time spent, the more conducive to accurate overprinting. If the half-finished product is replaced manually by hand, it must be handled lightly to prevent it from affecting the quality of the printed product.