Reasons and Solutions for Slow Drying of Products During Printing

Posted on 05-11-2024 by

The drying of ink during printing is mainly determined by the type and properties of the binder. There are many reasons for this, the main ones being as follows:

1. Moisture content of the plate: During the printing process, if the plate has excessive moisture, it not only causes the paper to absorb too much moisture and expand, but also forms a water-in-oil emulsified ink, thereby affecting the drying of the imprint.

2. Excessive addition of desiccant: Adding too much desiccant will cause the ink quality to become coarse, the plate to become dirty and sticky, the dot enlargement and deformation, and the imprint difficult to dry.

3. Excessive stacking of printed sheets: If the printed sheets have a large area, smooth surface, and are stacked too high, it will be difficult for air to come into contact with the printing ink, inevitably leading to slow drying of the imprint.

4. Temperature of the printing workshop environment: If the temperature is too low or the humidity is too high, it will slow down the drying of the ink.

5. Properties of the ink: Generally, inks prepared with organic pigments dry slower than those with inorganic pigments; thin binders dry slower than thick ones, and inks with higher oil content dry slower than those with lower oil content.

6. Reducer and leveller: Reducers and levellers both have properties that inhibit ink drying, so they should be added in small amounts.

7. Properties and structure of the paper: If the paper is acidic, the imprint will dry slowly. Paper with a rough surface, loose structure, high permeability, and low sizing degree will promote ink drying, whereas the opposite will slow down drying.

8. pH value of the fountain solution: A high concentration of hydrogen ions (H+) in the fountain solution will react with metal salts in the ink, thereby inhibiting the drying of the ink on the paper surface.