Offset Reasons and Countermeasures for Offset Printing

Editor's note: Offset printing turns to occupy the market at its speed, but at the same time the cause of speed can lead to many corresponding printing failures. The following article lists several common rotary printing problems and their solutions.

· Flying ink:

Phenomenon: The ink scattered in the mist between the ink rollers to pollute the surroundings.
the reason:
<1> The ink is too thin and its viscosity is not suitable.
<2> The ink supplied to the ink roller is too thick or the oil film of the ink roller is not uniform.
<3> Static electricity occurs.
Countermeasures:
<1>Adding a wax additive to make the ink shorter and sticky.
<2> Reduce the ink supply and adjust the ink roller pressure to make the film uniform.
<3> Humidification.

·Air drying:

Symptoms: The ink dries on the fountain or roller.
the reason:
<1> The room temperature is too high and the printer's temperature is too high.
<2> The solvent in the ink is too volatile or there is less drying inhibitor in the ink, and the ink is not suitable.
Countermeasures:
<1> Decrease the room temperature and reduce the circulating water temperature of the printing roller.
<2> Replace with new ink.

·Ink roller deinking:

Phenomenon: Insufficient ink transfer volume, reduced print density, and white metal transfer roller on printer.
the reason:
<1> The ink has poor water resistance.
<2> The printing water supply is too large and the ink and ink balance is out of balance.
Countermeasures:
<1> Add anti-water additives to the ink.
<2> Reduce the water supply and adjust the ink balance.

·Ink deinking:

Phenomenon: The ink is detached from the ink in the ink fountain, the ink transfer amount is insufficient, and the print density is reduced.
the reason:
<1> The ink does not have good fluidity.
Countermeasures:
<1> The ink in the fountain is often stirred to maintain its proper fluidity.
<2> Replace the ink with good fluidity.

· Paper pull phenomenon: White spots or print rollers tear the paper.
the reason:
<1> The ink viscosity is too high.
A. The ink itself has high viscosity.
B. The temperature of the printer is too high to make the ink solvent volatilize and the viscosity of the ink is increased.
C, printing room temperature is too low, low ink temperature makes the ink sticky.
<2> The printing roller has too much pressure on the paper.
<3> The paper strength is not good.
Countermeasures:
<1> Reduce the viscosity of the ink.
A. Add a suitable amount of high-boiling solvent.
B. Reduce the temperature of the printing solution and the ink roller circulating water to cool the printer.
C. Raise the room temperature or preheat the ink at standard room temperature.
<2> Adjust the printing roller pressure.
<3> Replace the stronger paper.

Ring white spot:

Phenomenon: There is a round core-shaped ring around the dots of an ink in the printed product.
the reason:
<1> The impurities in the ink adhere to the plate.
<2> The paper dust is peeled off and stuck on the plate.
<3> Dust particles or other materials on the printing press.
Countermeasures:
<1> Wash plate to remove impurities and replace new ink without impurities.
<2> The plate cleaning removes impurities and replaces paper that does not come off paper powder.
<3> Wash plate to remove impurities.