Good ink wash color change in offset printing

In the offset printing process, especially the single-color offset printing press, regardless of Y, M, C, BK four-color printing, trademark, packaging and decoration often need to wash the ink to change color, the entire offset printing machine's ink system is cleaned, and then Put on new ink. The ink-washing device scraper is composed of a rubber knife, an ink receiving slot, and a tight adjusting screw.

The process of washing ink: Pour gasoline and car wash water on the roller, install the wiper in the position of the washing ink tank, and tighten the adjusting screw so that the rubber blade is at an angle of 40° to the surface of the ink roller corresponding to the offset printing machine. Contact, longitudinal and lateral movements of the ink roller, the old ink and gasoline on the ink system are continuously scraped through the rubber blade into the ink receiver.

Washing and changing the color of the ink is clean and thorough. It plays a key role in accurately grasping the hue of the printing. Only the ink wash can be used for hue printing. The ink color is bright and accurate. The following points must be noted in the actual washing and color changing operation:

1. The ink scraper device must be installed on the offset printing machine when the color change of the ink is washed or when other factors need to be cleaned. The eccentric pin on both ends of the ink collection slot is set aside during installation. Fixed in the open slot of the supporting shaft of the offset printing machine wall, the adjusting nut is fixed in the opening of the square block of the wall plate. Then start the offset press and turn the adjusting nut so that the blade of the rubber blade slowly contacts the surface of the ink stringer. The contact pressures of the adjusting screws at the left and right ends are required to be uniform. The rubber blade and the ink stringer are in uniform contact with each other. Full scrape ink.

2. When cleaning the ink, in order to completely and cleanly remove the ink and ink marks on all the ink rollers, it is better to spray the gasoline on the ink roller near the ink fountain area from the upper part of the ink delivery device. The waste ink flows from the top of the rubber blade into the ink collecting tank. After a period of cleaning, the ink roller can be cleaned.

3. Ink Transfer Parts After the ink roller and ink fountain have been cleaned, wipe them clean and clean them with a clean, soft, clean cloth that does not have fiber fluff and absorbs water.

4. Cleaning The position of the wiper of the ink-washing mechanism should be accurate. Maintain the same distance and the same contact pressure between the blade and the surface of the ink roller.

5. After cleaning, take the wiping cloth to stabilize the speed of the wiping. The offset printing machine must not let the wiping cloth get into the ink roller under the running condition.

6. To change the color when washing the ink, the operator must keep a proper amount when pouring gasoline from the upper ink roller, and do not splash the gasoline everywhere.

7. Smoking and open flames are strictly forbidden in the workshop to prevent fire during color change.

8. The operation status of the offset printing press must be taken care of when cleaning the ink roller.

1 Beware of the cuffs, hands, and clothing corners of your shirts. They are caught in the rollers or rollers and cause injuries.

2 Operator's T-shirt Workwear pockets are prohibited to carry box rulers, keys, coins, pencils, pens and other hard objects, and tools for ink scooping and repairing machines, to prevent them from falling into the ink roller and causing accidents.

9. Ink Wash Color Change Under normal circumstances, there are two cases. One is the change of light ink to dark ink, and the other is the change of dark ink to light ink.

1 light ink for dark ink method

The change of light color inks to dark inks is relatively easy, and it also saves time and effort for the ink roller cleaning. First, use an ink scoop to shovel out the light ink of the ink fountain. Just use a scraper to clean the light ink on the clean ink roller, and clean the ink residue, paper hair, and other debris left on the ink roller at the same time.

2 dark ink replaced by light color ink

Offset printing ink change color, dark ink replaced by light-colored ink, this time for the ink roller cleaning requirements are higher, more difficult to clean, the ink roller cleaning degree is higher, it requires light-color ink can not be dark ink Dirty, if the clean old ink on the ink roller is not completely clean will affect the color and hue is inaccurate, there will be dark ink in the light-colored ink, therefore, must wash the ink fountain, ink roller, ink shovel, etc. Then use the ink spatula to apply the color ink to the ink roller, start the offset printing machine, make the ink roller evenly coated with light-colored ink, and then wash it with gasoline.

If it is not clean, you can repeat it again until the ink roller is clean.

Reprinted from: China Packaging News