Do a good job in ink washing and color changing in

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Do a good job in ink washing and color changing in offset printing

in the process of offset printing, especially in monochrome Offset printing machines, whether y, m, C, BK four-color printing, trademark, packaging and decoration, it is often necessary to wash ink and color changing, clean the ink transmission system of the whole offset printing machine, and then replace with new ink. The ink scraper of the ink washing device is composed of a rubber knife, an ink receiving slot and an adjusting screw

ink washing process: pour gasoline and car washing water on the ink roller, install the ink scraper in the ink washing position slot, tighten the adjusting screw, make the rubber knife contact the surface of the ink roller corresponding to the offset press at an angle of 40 °, and the ink roller moves longitudinally and horizontally, scraping and washing the old ink and gasoline on the ink conveying system into the ink receiving slot through the rubber knife in an important strategic opportunity period when they are still in development

wash the ink and change the color with an infinite amount of wood powder, and wash it thoroughly and thoroughly, which plays a key role in accurately grasping the printing hue. Only by washing the ink can the printed matter have a positive hue, and the ink color is bright and accurate. In the actual process of washing the ink and changing the color, we should pay attention to the following points:

1 The ink scraper device for ink washing can only be installed on the offset press when the ink is washed and changed, or when the ink roller needs to be cleaned due to other factors. During installation, the eccentric pin shafts at both ends of the ink receiving tank are placed in the open groove of the support shaft fixed on the offset press wallboard, and the adjusting nut is fixed in the opening of the square iron block on the wallboard. Then start the offset press, and screw the adjusting nut, so that the blade of the rubber knife slowly contacts the surface of the inking roller. The contact pressure of the adjusting screws at the left and right ends is required to be uniform. The rubber knife contacts each part of the inking roller evenly, which can scrape the ink comprehensively

2. When cleaning the ink, in order to thoroughly and cleanly remove the ink accumulation and ink marks on all ink rollers, it is best to sprinkle gasoline on the ink roller near the ink bucket area from the upper part of the ink conveying part, so that the waste ink from the cleaning will flow into the ink receiving tank from the upper part of the rubber knife edge, and after a period of cleaning, the ink roller can be cleaned

3. After the ink roller and ink bucket of the ink conveying parts are cleaned, wipe them clean, and clean them with a clean, soft, tidy cloth head without fiber nap and with good water absorption performance

4. The installation position of the ink scraper of the cleaning and washing mechanism should be accurate, and the rubber blade and the surface of the inking roller should be kept at the same distance and the same contact pressure

5. After cleaning, take the wiping cloth steadily and wipe it quickly. Don't let the wiping cloth get involved in the ink roller when the offset press is running

6. Ink washing and color changing requires the operator to keep an even amount of gasoline when pouring it from the upper ink roller. China's instrument industry will also produce new changes and achieve new development, and do not splash gasoline everywhere

7. Smoking and open flames are strictly prohibited in the workshop to prevent fires during ink washing and color changing

8. When the offset press is running, you must pay attention to safety when scrubbing the ink roller

① be careful that the cuffs, hands and corners of the jacket are entangled by the ink roller or roller, causing human injury

② it is forbidden to carry box rulers, keys, coins, pencils, pens and other hard objects, as well as ink shovels and repair machine tools in the pocket of the operator's work clothes to prevent them from falling into the ink roller and causing accidents

9. Generally speaking, there are two situations for ink washing and color changing: one is to change light color ink into dark color ink, and the other is to change dark color ink into light color ink with the most serious energy surplus crisis at the beginning of the year

① method of changing light ink into dark ink

it is easier to change light ink into dark ink, which saves time and effort for ink roller cleaning. First, use an ink shovel to shovel out the light color ink from the ink bucket. As long as you use an ink scraper to clean up the light color ink on the ink roller, and at the same time, clean up the ink skin, paper wool and other debris left on the ink roller

② replace dark ink with light ink

offset ink washing and color changing, and replace dark ink with light ink. At this time, the cleaning requirements for the ink roller are high, and it is difficult to clean, and the cleaning degree of the ink roller is high. It requires that the light ink cannot be polluted by the dark ink. If the old ink on the ink roller is not completely cleaned, the color and hue will be inaccurate, and there will be the shadow of dark ink in the light ink. Therefore, the ink bucket, ink roller Clean the ink shovel, and then apply the light color ink to the ink roller with the ink shovel, start the offset press, let the light color ink stick evenly on the ink roller, and then pour gasoline to clean it

if it is not clean, you can also repeat it until the ink roller is clean

reprinted from: China Packaging News

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