Causes and Countermeasures of Common Faults in Sheetfed Ink

1. Ink deinking:

Phenomenon: The ink is deinked (not grooved), the ink supply is reduced or interrupted, and the color of the printed product becomes lighter.

Reason: <1> Ink is too short and fluidity is too small.
<2> The thixotropy is too large and the viscosity is too small.

Countermeasures: <1> Join new liquid inks.
<2> Add a binder with a higher viscosity to increase the ink slope.

2. Pull paper hair:

Phenomenon: There is a small amount of paper pulled from the surface. Causes the printing product to be scrapped.

Reason: <1> The ink is too viscous.
<2> Poor surface strength of paper.

Countermeasures: <1> Add TPP-041 pull paper inhibitor to reduce ink stickiness.
<2> Use paper with high surface strength.
<3> Reduce the speed of the printing press.

3. Ink powdering:

Phenomenon: After the ink is dry, there is a little pressure and it is easy to wear away.

Reason: <1> There are few film-forming substances in the ink.
<2> The viscosity of the ink is too small.
<3> The ink is poor in water resistance (emulsification).
<4> The paper is too ink-absorbent.

Countermeasures: <1> Improve the composition of the film-forming substance, such as adding high-viscosity resin oil.
<2> Reduce the acidity of the medicine to reduce the amount of water.
<3> Replace less absorbent paper.

4. Dry slowly:

Phenomenon: 48 hours quit, the blot can easily be erased.

Reason: <1> Insufficient desiccant in the ink.
<2> The ink has poor water resistance.
<3> Ink storage deteriorates the desiccant effect.
<4> Excessive amount of wetting powder added.

Countermeasures: <1> Add an appropriate amount of desiccant to the ink.
<2> Improve ink water resistance.
<3> Adjust the pH of the medicine and reduce the amount of wetting powder added.
<4> Add TPP-002 printing syrup desiccant to the printing solution.

5. Heap eraser:

Phenomenon: The ink piled up on the blanket and was not transferred to the paper.

Reason: <1> The ink is too short to resist water and poor ink emulsification.
<2> There are too many pigments or fillers used in the ink.
<3> The paper is powdered.
<4> The amount of anti-adhesion agent added is too large.

Countermeasures: <1> Reduce the amount of anti-adhesion agent added.
<2> Increase the length of the ink and increase the water resistance.

6. Ink roller stack:

Phenomenon: The ink on the roller cannot be transferred, the density of the printed sample is not enough, the parking water evaporates, and then the car is driven. The density exceeds the requirement.

Reason: <1> Ink water resistance is not good.
<2> ink ink is too short.
<3> The viscosity of the ink is too small.
<4> The amount of printing syrup is too large.

Countermeasures: <1> Check the ink viscosity and fluidity.
<2> Improve ink water resistance.
<3> Reduce the amount of water or isopropyl alcohol added to improve the wettability and increase the volatility.

7, from the greasy:

Phenomenon: There is a layer floating net point in the layout is not clear.

Reason: <1> Ink resistance is too poor <2> Insufficient ink viscosity.

Countermeasures: <1> Increase the ink viscosity and add TPP-101 external oil.
<2> Adjust the printing solution, add isohexol or alcohol, and reduce the surface tension.

8, dirty version:

Phenomenon: Can't keep the non-image part clean.

Reason: <1> The ink is too soft and its viscosity is too small.
<2> The pressure of the ink roller is in the order of failure.
<3> Plates are not sensitive enough.
<4> The ink has poor water resistance.

Countermeasures: <1> Add TPP-101 external oil.
<2> Add isohexyl alcohol to the fountain solution to reduce the surface tension or increase the amount of water.
<3> Check the surface of the dampening roller for good water absorption and oil removal.
<4> Adjust the pressure on the plate roller.

9, fly ink:

Phenomenon: The droplets of ink droplets that form between the rollers are scattered around the machine and pollute the environment.

Reason: <1> The ink supplied to the ink roller is too thick or the ink film of the ink roller is uneven.
<2> The ink is too long or the viscosity is too small.
<3> The ink roller is worn or damaged, or it is not installed properly.

Countermeasures: <1> Reduce the ink supply or adjust the ink roller pressure to make the ink film uniform.
<2> The addition of a wax assistant makes the ink ink shorter.
<3> Check if the ink roller is damaged and the installation is reasonable.
<4> Reduce the printing speed.



Source: HC Network