How to reduce ghosting problems during the printing process

Often encountered in the printing process "ghosting" problem, this time, film, printing plate has been made, the revision is not realistic, the only way can be taken in the printing stage to minimize ghosting phenomenon. The following will introduce Mitsubishi 3F offset press to introduce how to minimize ghosting failures.

1. cause

A picture we want to print. Because there are vertical ink sticks in the middle of the two horizontal ink sticks, the corresponding circumferential direction of the vertical ink sticks requires a larger amount of ink. However, in the high-speed printing, if the ink roller cannot be supplied with sufficient ink in time, or if the ink corresponding to the vertical bar is less than the amount of ink in other parts, the ink-ejection ghost is easily generated.

2. Troubleshooting

Although the following methods cannot completely eliminate ghosts, they can be reduced to almost invisible levels.

(1) Adjust the ink supply system. Since the layout of the vertical bar requires a large amount of ink, we can increase the ink volume of the ink key corresponding to the vertical bar to supplement as much ink supply as possible for that portion. However, due to the axial movement of the ink string roller, in order to ensure the uniform ink color of the entire bar, the amount of ink should be reduced on both sides of the corresponding part of the vertical bar. This amount of ink plus the amount of ink in the chain can basically ensure the evenness of the ink in the bar.

(2) Control dampening mode. Mitsubishi 3F offset press has 3 kinds of dampening modes to choose from. There are 3 ways to switch at any time on the remote console. When ghosts appear, another form of dampening is generally used. In this dampening mode, since the transfer roller 2 is separated from the ink form roller 5 and the distributing roller 6, the ink remaining on the watering roller 1 cannot be transmitted, so that these excess inks can be used as a supplement to the ink-repelling portion of the plate. To reduce ghosting. The dampening roller of the dampening method has the lowest rotation speed and the ink emulsification degree is small.

(3) Adjust the amount of water supply. We know that in the printing process, the ink balance is a relative balance. The balance of the ink and ink can be achieved when the amount of fountain solution in the ink is between 15% and 26%. When the dampening solution is controlled in the ink-water-less balance, the ink emulsification value is the smallest, relatively speaking, the same amount of the transferred ink, the degree of emulsification is small, and the ink content in the printing product is high, so the ink is saturated and vivid. , To a certain extent, can reduce the ghost effect.

Through the joint action of the above three methods, the effect of ghosting failures in the printing process can be reduced to a minimum, thereby improving the quality of printed products. This method is very effective in practical operation and can directly print out high-quality products without changing the design and process of printed products.