Analysis and countermeasures of abnormal ink quality

- Dec 20, 2019-

Bad hue often appears in printing. Hue refers to the saturation and vividness of the color. What are the reasons for this?

There are roughly eight reasons:

1. Ink viscosity or color density is too low

2. Ink and water separation and precipitation

3. Poor ink transfer

4. Too much residual water

5.Rubber roller is too high

6. The hardness of the rubber roller is too high

7. The pressure of the scraper on the surface of the anilox roller is too large

8. The scraper blade contact surface is too strong


What should I do after finding these reasons?

1. If the ink viscosity or color density is found to be too low during the printing process, add new ink to the ink bucket. If the number of orders made is not large, you can take a separate sheet, that is, send one sheet and stop one. Send again, let the anilox roller and printing plate eat thick ink


New ink is measured every second before printing on the machine. I have already said how to measure it, so I wo n’t say it here.


2. Water and ink are separated and precipitated. Before the new ink is printed on the machine, shake the ink tank evenly, and then pump the ink to the anilox roller with an ink pump.


If it is in the printing process, without adding new ink, the ink tank can be shaken evenly, and then the ink is re-filtered with a sand screen to separate the sediment in the ink.


3. When the ink transfer is poor, the surface of the anilox roller, rubber roller, and printing plate is likely to be dirty. If so, it will be fine after cleaning.


4. When there is too much residual water, it is necessary to unblock the water and ink pipeline. It may be that the inclination angle of the ink return pipe is not enough. Readjust to reduce the residual water.


5. The middle height of the rubber roller is too high. If the middle height of the rubber roller exceeds the standard, you need to remove the rubber roller and regrind the middle height.


6. The hardness of the rubber roller is too high, the rubber roller needs to be removed and re-glued and ground.

The hardness of the encapsulation is generally between 60 and 70 degrees. The hardness varies depending on the rubber used.


7. The pressure of the scraper pressing on the surface of the anilox roller is too large. Re-adjust the pressure of the scraper pressing on the anilox roller. After renewing the scraper blade, readjust it.


8. The contact surface of the scraper blade is too strong. The angle of the scraper blade is usually 30 degrees, 45 degrees, and 60 degrees. Modify the thinner scraper blade as required.