Experience of four-color printing with the hottest

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Experience of printing four-color color color with monochrome machine

printing four-color color with monochrome Offset printing machine has many variable factors and strong technicality. The following is some experience and experience I accumulated when printing four-color color color with monochrome machine

1. before printing, carefully check whether the printing quality is qualified, and repair the page to apply for a PCT patent. 1 piece of redundant dirty spots and lines

2. Before starting the machine, carefully adjust the Feida, paper feeding roller, side pull gauge and the handover time of each part of the machine to make the machine run smoothly, the pull gauge pulls the paper in place, and the handover time of the paper at each part is accurate. Then adjust the roller pressure and adjust the amount of ink required for printing by passing through the master paper

3. the color sequence is yellow, magenta, cyan and black. Whether from the transparency or viscosity analysis of ink, this kind of color sequence arrangement is more scientific. Put yellow on the first color for printing, and the slight beating of rules has little effect on the overall printing effect. When printing yellow ink, you can also better observe and adjust the machine to facilitate the accurate overprint of the last three colors. However, the color sequence of monochrome machine is not invariable, and it should be reasonably selected according to the characteristics of printing materials and originals. For example, the environmental factors with easy surface also play a role in the material selection of the car lampshade. When the paper with a large amount of powder and impurities is removed, the one color with a small printing area should be printed on the front. In this way, after printing two colors, the paper powder and impurities are basically removed, and the large layout of the rear printing can be flat and free of dirty spots, and the overall effect of the print is good

4. Carefully analyze the viscosity, fluidity, drying time and paper quality of the ink before printing. It can measure whether the relevant physical properties of the test piece meet the use requirements to the greatest extent. Adding additives to the ink reasonably is conducive to the improvement of print quality

5. After the machine runs normally and the ink volume is adjusted, be sure to stir the ink bucket frequently and add more or less ink, so as to maintain a certain amount of ink in the ink bucket and ensure the normal supply of ink. Observe the water content of the page frequently, and use the least amount of water on the premise of not getting dirty, so as to balance the water and ink, keep the ink color consistent, and avoid paper elongation due to large water, so as to facilitate accurate overprint. Observe the prints frequently and compare the samples carefully to ensure that the ink color of the prints is consistent. We should always check the overprinting condition, so as to adjust the machine in time to make the overprinting of printed products accurate. When printing the first color, the accuracy of the rules should be observed by drawing a sideline. In addition, we should also pay attention to whether the printed matter has sticking back. If so, we should timely use measures such as placing more partition plates, frequently taking printing sheets, and dusting (dusting can only be used in the last color). Before restarting each time, you should walk over the master paper to ensure that the ink color of the printing is consistent

the shorter the time it takes to print four-color color with a monochrome machine, the more conducive it is to accurate overprint. If the semi-finished products are manually aligned when changing the version, be sure to handle them with care to prevent affecting the quality of the printed products

cause analysis and treatment of "ghost" failure of Mitsubishi 3F offset press

Wang liangbing

date: March 30, 2005

the problem of "ghost" often occurs in the printing process. At this time, the film and printing plate have been made, and the revision is unrealistic. The only way to take is to try to minimize the ghost phenomenon in the printing stage. The following will introduce how to minimize the ghost fault in combination with Mitsubishi 3F offset press

1. Cause

a picture we want to print. Since there is a vertical bar ink block between the two horizontal bar ink blocks, the corresponding circumferential direction of the vertical bar ink block requires a large amount of ink. However, in high-speed printing, if the inking roller cannot be supplemented with enough ink in time, or the ink volume of the horizontal bar corresponding to the vertical bar is less than that of other parts, it is easy to produce the ghost of ink shortage

2. Fault handling

although the following methods can not completely eliminate the ghost, they can reduce it to an almost invisible level

(1) adjust the ink supply system. Since the layout with vertical bars requires a large amount of ink, we can increase the ink volume of the ink key corresponding to the vertical bars and supplement the ink supply of this part as much as possible. However, due to the axial movement of the inking roller, in order to ensure the uniformity of the ink color of the whole horizontal bar, the ink volume should be reduced on both sides of the corresponding part of the vertical bar. This ink amount plus the ink amount from the series movement can basically ensure the uniformity of the horizontal bar ink amount

(2) control the fountain method. Mitsubishi 3F offset press has three ways to moisten the plate. The three modes can be switched at any time on the remote control console. When ghosts appear, another form of embellishment is generally used. In this way, since the transfer roller 2 is separated from the inking roller 5 and the inking roller 6, the ink retained on the inking roller 1 cannot be transferred, so these excess ink can be used as a supplement to the ink lacking part on the plate, so as to reduce the ghost. The fountain method has the lowest number of revolutions of the bucket roll and the low degree of ink emulsification

(3) adjust the water supply. We know that the ink water balance is a relative balance in the printing process. The ink water balance can be achieved when the content of fountain solution in the ink is between 15% and 26%. When the fountain solution is controlled at the balance of more ink and less water, the ink emulsification value is the smallest. Relatively speaking, in the same amount of transferred ink, the emulsification degree is small, and the ink content in the print is high, so the ink color of the print is saturated and bright, which can weaken the ghost effect to a certain extent

through the joint action of the above three methods, the ghostly shadow also needs to be stable in the printing process, and the influence of the operation barrier can be basically reduced to a small extent, so as to improve the quality of printing products. This method is very effective in practical operation, and high-quality products can be printed directly without changing the design and process of prints. (Liang Lijun)

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