Common Faults and Solutions of Offset Transfer Printing Inks

Flying ink:
Phenomenon: The ink scattered in the mist between the ink rollers to pollute the surroundings.
Reason: <1> The ink is too thin and sticky.
<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> Add wax additives to make the ink shorter and stick out.
<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.
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> Reduce 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.
Reason: <1> Ink resistance is not good.
<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.
Reason: <1> Insufficient ink flow.
Countermeasures: <1> The ink in the ink fountain is often stirred to maintain its proper fluidity.
<2> Replace the ink with good fluidity.

· Pull paper hair:
Symptoms: The printed product has white spots or the printing roller tears the paper.
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.

·Circular white spot:
Phenomenon: There is a round core-shaped ring around the dots of an ink in the printed product.
Reason: <1> The impurities in the ink are stuck on 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.

· Repository:
Phenomenon: Ink or ink mixture accumulates on the printing plate and like cloth, the printing picture area appears the partial ink is shallow or sends the flower.
Reason: <1> The ink has poor fluidity after emulsification, and the transfer is not good.
<2> Paper powder or paper wool is mixed with ink and accumulated on the plate.
Countermeasures: <1> Replace the ink with good water resistance, or add anti-water additives.
<2> Replace paper with low paper dust.

· Printing plate non-graphic area dirty:
Phenomenon: There is ink on the non-graphic area visible on the print.
Reasons: <1> Ink is not emulsified after emulsification.
<2> The fountain solution has a large surface tension, and the non-graphic area of ​​the plate is not well inked.
<3> Ink roller and plate pressure are too large.
Countermeasures: <1> Replace the ink with good water resistance.
<2> Increase the IPA content.
<3> Adjust the ink roller and layout pressure. · Off-page:
Phenomenon: In the printing area, the graphic area is poorly inked, and the print density is reduced or the picture is not complete.
Reason: <1> The plate is poorly greaseed.
<2> The paper powder that has come off the surface of the paper is worn by the plate surface.
<3> Insufficient printing pressure causes the image film of the plate to be worn off.
<4> Too much pH solution in the fountain solution causes the plate to corrode and the graphic comes off.
Countermeasures: <1> Replace the new version.
<2> Replace better quality paper and use less viscous ink.
<3> Adjust the pressure, reduce wear.
<4> Pay attention to the adjustment of the fountain solution and add the PH solution at a reasonable ratio.

·Water roller stick ink:
Phenomenon: The ink on the transfer roller of the printer.
Reasons: <1> Ink resistance to poor ink emulsification.
<2> Water roller and plate pressure are not normal.
Countermeasures: <1> Replace the ink with good water resistance.
<2> Adjust the water roller pressure.

Bad overprint:
Phenomenon: After the color sequence ink overprint or not overprint.
Cause: <1> After the color sequence ink is more viscous than the preceding sequence ink, the previous color ink is pulled off.
<2> After the color sequence, the ink is pulled off before the ink is too large.
Countermeasures: <1> Change the color sequence or reduce the viscosity of the ink after the color sequence.
<2> Reduce the color press of the color printer after adjustment.

Bad drying:
Phenomenon: poor drying of ink, sticky ink on the cooling roller.
Reason: <1> The surface temperature of the paper reaching the box is not high enough, so a considerable amount of solvent in the ink cannot be removed.
<2> The cooling effect of the web after printing is not good.
<3> The paper used has poor absorbency or the print has too much ink.
Countermeasures: <1> Increase the paper surface temperature or reduce the print speed.
<2> Reduce the cooling drum temperature.
<3> Reduce the ink supply or use absorbent paper.

· Paper breaks:
Phenomenon: The printed product will crack when folded.
Cause: The oven temperature is too high and the paper is dehydrated.
Countermeasures: Reduce the oven temperature.

· Bad rubbing resistance:
Phenomenon: The print is not resistant to rubbing and discoloration.
Reason: <1> Low oven temperature Thermoset ink is not completely dry.
<2> The pH of the dampening solution is too low and the print is not drying properly.
<3> Strong Absorptivity of Paper Absorber
<4> There are few anti-friction additives in the ink.
Countermeasures: <1> Increase the oven temperature to dry the prints thoroughly.
<2> Increase the pH of the fountain solution.
<3> Select moderately absorbent paper.
<4> Replace the new ink and add a rubbing aid afterwards.

· Bad gloss:
Phenomenon: The brightness of the printed product is not enough and the gloss is low.
Cause: <1> The supply temperature was too high, resulting in thinning of the binder in the ink and excessive penetration of the paper.
<2> The print is not completely dry.
<3> Insufficient ink or low gloss of the paper itself.
Countermeasures: <1> Reduce the oven temperature and adjust the appropriate paper surface temperature.
<2> Adjust the temperature and printing speed so that the print is completely dry.
<3> Select high-gloss paper to increase the amount of ink in the print.

·Ghosting:
Phenomenon: Two or more identical prints appear on the print.
Reason: <1> Mechanical ghosting: Loosening of the plate or blanket.
<2> Imprint overprinting is not allowed.
Countermeasures: <1> Adjust the plate and blanket.
<2> Adjust the rules of the printing press to improve overprint accuracy and exchange overprinting sequence.

· Inequality:
Phenomenon: The print product is uneven or the cross section of the printed product is wavy and uneven.
Reason: <1> The amount of printing water is too large to make the print water stained.
<2> The paper roll of the printing press has too much force to deform the paper.
Countermeasures: <1> Reduce the amount of water when printing.
<2> Adjust the tension force of the printer tension roller.

Reprinted from: Shenzhen Printing Network