How to Wash Ink and Change Color in Envelope Printing Process

How to Wash Ink and Change Color in Envelope Printing Process

In the envelope printing process, especially monochrome offset presses, whether Y, M, C, BK four-color printing, trademarks, packaging and decoration often need to wash ink and change colors, stop cleaning the entire ink delivery system of the offset press, and then Replace with new ink. The ink washing installation wiper is composed of a rubber knife, an ink receiving tank, and a loose adjustment screw.

The process of ink washing: pour gasoline and car wash water on the ink roller, place the wiper device in the ink washing slot, tighten the adjustment screw, make the rubber knife at a 40° angle to the surface of the ink string roller corresponding to the offset printing machine In contact, the ink string roller moves longitudinally and laterally, and the old ink and gasoline source on the inking system are scraped into the ink receiving tank through a rubber knife from time to time.

The ink wash and color change are clean and thorough. The precise grasp of the printing hue plays a key role. After the ink wash, the printed product can have a positive hue and bright and accurate ink. Pay attention to the following points in the practice of the ink wash and color change operation:

1. The wiper for ink washing must be installed at the time of ink washing and color change, or when the ink roller needs to be cleaned due to other factors, it can be installed on the offset printing machine. Fixed in the opening groove of the supporting shaft on the wall plate of the offset printing press, and fixing the conditioning nut in the opening tooth of the square iron block on the wall plate. Then start the offset printing machine and turn the conditioning nut to make the blade of the rubber rubber knife slowly contact the surface of the ink stringing roller. The contact pressures of the conditioning screws on the left and right ends are requested to be average. The rubber knife and each part of the ink stringing roller are in average contact. Scrape the ink completely.

2. When cleaning the ink, in order to thoroughly and cleanly remove all the ink accumulation and ink traces on the ink roller, it is best to pour gasoline on the ink roller near the ink fountain area from the upper part of the inking part. In this way, it is very clean. The waste ink flows from the upper part of the rubber knife edge into the ink receiving tank, and after a period of cleaning, the ink roller can be cleaned.

3. After cleaning the ink roller and ink fountain of the inking parts, wipe it clean, and stop the cleaning with a clean, soft, tidy, fiber-free cloth with good water absorption performance.

4. The position of the wiper device of the cleaning ink washing mechanism must be accurate, and the rubber blade and the surface of the ink string roller must be kept at equal intervals and the same contact pressure.

5. After the liquidation is clean, the speed of wiping with the wiping cloth should be fast, and the wiping cloth should not be caught in the ink roller when the offset printing machine is in operation.

6. When washing the ink and changing the color, the operator should insist on an average and proper amount when pouring gasoline from the upper ink roller, and don't splash the gasoline everywhere.

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

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

① Pay attention to the cuffs, hands and corners of the shirt, which are caught by the ink roller or roller, causing human injury.

②It is forbidden to carry box rulers, keys, coins, pencils, pens and other hard objects, ink shovel and repairing tools in the pocket of the operator's coat and overalls to prevent them from falling into the ink roller and causing accidents.

9. There are two conditions under normal conditions of ink washing and color change, one is changing light ink to dark ink, and the other is changing dark ink to light ink.

①The method of changing light-colored ink to dark-colored ink 　　It is relatively easy to change light-colored ink to dark-colored ink, and it is also time-saving and labor-saving for ink roller cleaning. First, use an ink spatula to shovel out the light ink of the ink fountain. You only need to use a scraper to clean the light ink on the clean ink roller, and at the same time, clean the ink skin, paper wool and other sundries left on the ink roller.

②Dark ink is changed to light color ink for offset printing and color change, and dark ink is changed to light color ink. At this time, the cleaning request of the ink roller is higher, and cleaning is more difficult. The cleaning level of the ink roller is higher, and it requires light color. The ink cannot be contaminated by the dark ink. If the old ink on the ink roller is not thoroughly cleaned, the color and hue will be imprecise. There will be shadows of dark ink in the light ink. Therefore, the ink fountain, ink roller, ink must be The shovel is cleaned, and then the ink shovel is used to apply the light-colored ink to the ink roller, and the offset printing machine is started, so that the ink roller is evenly coated with light ink, and then sprayed with gasoline to clean it off. If it is not clean, it can be repeated once until the ink roller is clean.