In the offset printing process, especially the monochrome offset printing machine, no matter Y, M, C, BK four-color printing, trademarks, packaging and decoration often need to wash ink and change color, clean the inking system of the entire 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 tank, and a tight adjustment screw.
Ink washing process: Pour gasoline and car wash water on the ink roller, install the wiper in the slot for ink washing, and tighten the adjusting screw so that the rubber knife is at a 40 ° angle to the surface of the ink roller corresponding to the offset press In contact, the tandem roller moves longitudinally and laterally, continuously scraping the old ink and gasoline on the inking system through the rubber knife into the ink receiving tank.
Ink-washing and color-changing are clean and thorough. They play a key role in accurately grasping the printing hue. Only by washing inks can the hue be correct, and the ink color is bright and accurate. In the actual process of ink-washing and color-changing, the following points should be noted:
1. The ink scraper device for washing ink must be installed on the offset printing machine when the ink is changed and the ink roller needs to be cleaned due to other factors. When installing, the eccentric pins at both ends of the ink receiving tank are placed on the It is fixed in the opening groove of the support shaft on the wall plate of the offset press, and the adjusting nut is fixed in the opening of the square iron block on the wall plate. Then start the offset printing machine and turn the adjusting nut to make the blade of the rubber knife slowly contact the surface of the ink roller. The contact pressure of the adjusting screws on the left and right ends needs to be uniform. The rubber knife and each part of the ink roller are evenly contacted. Scrape ink completely.
2. When cleaning the ink, in order to completely and cleanly remove all the accumulated ink 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 unit. Waste ink flows into the ink receiving tank from the upper part of the rubber knife edge. After a period of cleaning, the ink roller can be cleaned.
3. After the ink rollers and ink fountains are cleaned, wipe them clean, and clean them with a clean, soft, neat fiber-free lint and good water absorption cloth head.
4. The installation position of the wiper for cleaning the ink washing mechanism should be accurate, keeping the equal distance and the same contact pressure between the rubber blade and the surface of the ink roller.
5. After cleaning, the wiping cloth should be wiped firmly and fast, and the offset printing machine should not allow the cloth to roll into the ink roller when it is running.
6. Washing ink and changing color require the operator to keep a proper amount when pouring gasoline from the upper ink roller, and avoid splashing gasoline around.
7. Smoking and open flames are strictly prohibited in the workshop to prevent fires when washing ink and changing colors.
8. The running state of the offset printing machine, the scrubbing ink roller must pay attention to safety.
â‘ Be careful that the cuffs, hands and corners of the jacket are caught in the ink roller or roller, causing injury to the human body.
â‘¡It is forbidden to carry box rulers, keys, coins, pencils, pens and other hard objects as well as ink shovel and machine repair tools in the pocket of the operator's work clothes to prevent it from falling into the ink roller and causing accidents.
9. Washing ink and changing color There are two situations under normal circumstances. One is to change the light ink to dark ink, and the other is to change the dark ink to light ink.
â‘ How to change light ink to dark ink
It is easier to change the lighter color ink to the darker color ink. It also saves time and effort for cleaning the ink roller. First, use an ink shovel to shovel out the light-colored ink of the ink fountain. Just use a wiper to clean the light-colored ink on the ink roller, and at the same time clean the debris such as ink skin and paper wool left on the ink roller.
â‘¡Dark ink is replaced with light ink
The offset printing ink changes color, and the dark ink is changed to light ink. At this time, the cleaning requirements of the ink roller are higher, and the cleaning is more difficult. The cleaning degree of the ink roller is higher. It requires that the light ink cannot be used by the dark ink Dirty, if the old ink on the ink roller is not completely cleaned, it will affect the color and hue inaccuracy. There will be dark ink shadows in the light ink. Therefore, the ink fountain, ink roller, ink shovel, etc. must be cleaned. Then use the ink shovel to apply the light color ink to the ink roller, start the offset printing machine, and evenly attach the light color ink to the ink roller, and then pour gasoline to clean it.
If it is not clean, you can repeat it again until the ink roller is clean.
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