In gravure printing, the adjustment of the doctor blade includes the following.
The doctor blade position
The position refers to the distance between the blade contact position and the paper contact position on the cylinder. The printing speed and drying speed of ink can influence the distance. If the printing speed is high and the drying speed of ink is low, the longer distance is necessary.
The contact angle of blade
The contact angle of the doctor blade should be the same whether it is a standard doctor blade or other type doctor blade. The best contact angle is 60 degrees, which can ensure the effect of removing excess ink and the quality of the print, reducing cylinder wear.
The pressure of doctor blade
The pressure of the blade can prevent the shifting of the doctor blade resulting from the rotating of the cylinder. The pressure depends on printing press type, the depth of print color, printing order of different colors, the thickness and hardness of doctor blade. After ensuring the efficiency of removing excess ink and good controlling of the ink quantity, the pressure should be as small as possible to reduce the wear of the cylinder.