ã€Chinese Packaging Network News】 During the production of printing, if the wetting fluid is used excessively, problems such as overprinting, back sticking, and poor drying may occur, scratching the skin, and deducting rubber. In particular, the deduction of rubber, which includes the paper hair buckled on the surface of the rubber, paper powder and even the paper on the printing plate, ink residue and so on. These problems can affect product quality and affect the production schedule, and even cause serious quality accidents. What are the reasons that easily lead to "buckle rubber"? There are six main aspects.
1, the pressure is too light
The pressure of the printing plate and the rubber cover is too light, and the paper hair and paper powder buckled on the rubber cover cannot be transmitted through the printing plate; the pressure of the rubber cover and the pressure roller is light, so that some fine impurities cannot be compacted and taken away on the paper surface. The residue on the rubber; printing plate contact with the printing roller by the pressure is not true, can not keep the plate residual paper, paper powder, etc., leaving the printing plate heap ink, sticky slag and so on.
2, the paper surface roughness
The printed texture is soft, with rough surface, slag, powder, etc. It is easy to adhere to the rubber.
3. The gasket is not even
The printing plate or rubber pad is not even and uneven, and the lower position is likely to accumulate paper hair, paper powder, etc., resulting in partial buckle rubber.
4 ink viscosity
Ink viscosity is too large. Paper peeling force on the surface of the paper, paper on the paper, paper powder, etc. are easily hidden down, severe pull hair, peeling phenomenon.
5. More ink impurities
In the ink fountain, there are too many impurities in the oil or too much paper on the roller, which is transmitted to the printing plate through the roller.
6. Uneven water
When there is water on the side of the water roller or when there is a small amount of water, the wear of the ink is increased compared to other places, resulting in serious deducting of rubber in the water.
In the face of these six issues, how to solve them one by one?
1. Try to choose a paper with a solid texture, even pulp, and a smooth surface.
2. Adjust the contact pressure between the ink rollers, the contact pressure between the plate roller and the plate roller, and the contact pressure between the water rollers.
3. Ensure that the ink is clean and free of ink residue, paper hair and other impurities, and stir the ink in the ink fountain. Clean the ink roller frequently and keep it clean.
4. Plates and rubber pads must be flat and clean.
5. The pressure should be slightly larger than normal printing. Try not to turn the pressure gauge so as not to affect the overprint. We have adopted a method of adding 0.09 to 0.15 mm backing paper in the rubber pad. For a two-color machine. The first color to increase the pad, the second color can be fixed. For four-color machines, one-color, two-color increase pad, three-color, four-color unchanged, one color should be slightly thicker than the two-color pad. Doing so will cause the full-page change to be 0.01 to 0.02mm, which will not cause too much error in overprinting (Note: After adding the backing paper, the blanket should be pressed tightly, otherwise overprinting will be affected).
6. Appropriate addition of ink in the ink reduces the viscosity of the ink. General graphic products should be added 3% to 5% of the relieving agent and 1% to 3% of the varnish; For thick ink products in the field, it is necessary not only to add and remove adhesives and varnish, but also to add about 2%. Dusting powder; printing gold, silver plus 2% to 3% of the escaping agent, can also reduce the "buckle rubber" phenomenon. Light quality water roller should reduce the amount of material to avoid floating on the dirty; velvet water roller can increase the amount of attached department. For quality requirements, printing with coated paper should be minimized or not used to ensure that the ink is bright and shiny. Do not apply retackifiers for those that require hanging plastics.
No matter what kind of reasons lead to "buckle rubber", as long as we carefully observe, combined with the machine's consistent situation, comprehensive analysis and judgment, the problem can be solved.