The cause of the "oily" phenomenon in the printed matter

Dirty oil can be divided into two categories: one is due to the blank part of the layout of the ink fat, greasy state, commonly known as "greasy"; the other is due to the ink emulsified with fine particles evenly distributed in the layout, commonly known as " Dirty." The causes of dirty oil are:

(1) Plate

a. The printed body is not of high quality (bad edition or recycled version);

b. Insufficient exposure time during exposure and developer concentration too low;

c. The printing plate's protective glue is not clean;

d. The blank part of the printing plate is oxidized;

(2) printing machine

a. Pressure on the plate is too light;

b. The pressure between the water rollers is too light;

c. ink viscosity is too low;

d. Aging of the blanket surface;

e. paper powder and paper wear plates;

f. Incorrect pH of fountain solution.