Abstract:

While drying, conventional offset inks dry by evaporating volatile components (solvents) into the surrounding air. Also, they dry by absorbing the binders into the printing substrate. Some modern offset ink dries exclusively by setting the binders without having a mentionable amount of volatile components.

The drying process may be disturbed or delayed if some surrounding requirements are not given or application errors apply.

If the drying of the ink is heavily affected, setting ink to the following sheets in the pile is very likely to happen. I major cases, the whole pile may block. Also, additional dirtiness of the press and additional cleaning efforts may follow.

 

Suspect 1 – Ink/Fountain Solution not working well together

It is a basic requirement in the offset world that all process-related components are tested or approved for prober interaction and compatibility. 

Redeem:

  1. Talk to your consumables supplier or press manufacturer for advice
  2. Check fountain solution additives for proper concentration
  3. Check if micro-particle filters do not filter out working ingredients of the fountain solution (bypass for testing)

 

Suspect 2 – excessive dampening

Over emulsification of the ink will delay the drying process as the water needs to evaporate for complete drying

Redeem:

  1. Minimize dampening to the lowest threshold to maintain plates free of scumming

 

Suspect 3 – Air conditioning

The surrounding air needs to be able to accept the additional water exiting the printed stock. 

Redeem:

  1. Make sure, the air is conditioned to a relative humidity not exceeding 70%

 

Suspect 4 – Deliver-Pile not tempered probably

The pile temperature in the delivery shall be slightly higher than the feeding substrate. If the pile is too cold the humidity may not be released as fast as possible. If the pile temperature is too high, the ink is kept too soft to cure.

Redeem:

  1. Make sure the stock is climatized to pressroom temperature before processing it.
  2. Adjust pile temperature using Infrared Emitters (IR) to be at a temperature plus 10-15 Degrees Celsius compared to the feeding pile. In the case of coating with aqueous varnish, use hot air instead of IR to adjust. (See Suspect 5)
  3. Recommendation:  35 Degrees Celsius (95 Degrees Fahrenheit )

 

 Suspect 5 – Wrong heating system used

Using water-based coatings, the extra humidity from the varnish needs to be released. Otherwise, the drying process might be delayed enormously.

Redeem:

  1. Use only hot-air dryers and hot air exhaustion, if available. 

 

Suspect 6 – Coating squeezed into the ink

If the coating is smashed into the ink with excessive pressure, the drying process is heavily affected

Redeem:

  1. Reduce the pressure of the coating form to the substrate to the very minimum possible

 

Suspect 7 – Too much coating applied

The more coating applied, the more water is held by the pile to release before back-side printed or further processing.

Redeem:

  1. Reduce the amount of applied coating by selecting an anilox roller with a lower charge
  2. Check coating chamber doctor blades and renew if worn out 

 

Suspect 8 – Ink film too heavy

If the applied amount of ink is too much for the given substrate, drying delay occurs

Redeem:

  1. Reduce overall density t te lowest acceptable level
  2. Re-Calibrate the process using lower densities

 

Suspect 9 – Total amount o fink too high

The total amount of ink used for every color-separation is controlled by the ICC-profile. An unsuitable simulation profile may cause the use of an unsuitable tota amount of ink for the given substrate. If the substrate is not able to absorb the applied ink, drying may be delayed or prevented at all.

Redeem:

  1. Deploy an ICC-profile set to a lower Total Amount of Color (TAC)
  2. Fingerprint the press using lowest solid densities possible and create an individual ICC-profile with a TAC limited to 280%-300%

 

Suspect 10 – substrate PH too high

If the PH-value of the substrate exceeds 8, drying issues are very likely. Only applicable to papers.

Redeem:

  1. Try another substrate if possible
  2. Pre-Coat (Prime) the substrate
  3. Contact your substrate supplier

Offset Ink Drying Issues

Abstract: While drying, conventional offset inks dry by evaporating volatile components (solvents) into the...

Coating Chamber Leaking

How to address leaking/slinging coating units in industrial printing machinery.

Pile Blocking

How to address blocking piles after press delivery (Offset)

Framing

Picture Framing. An printing issue were ink is getting transferred over non-printing area

Ink Misting

Ink misting. Dirty printing presses caused by Ink-Aerosoles.

Streaking (Offset)

Streaks in print are color density fluctuations or contrast variations, usually perpendicular to the print direction.

Piling

  Abstract Piling is an unwanted effect, where the pigments of the ink build-up negatively on the blankets. Serious...

Streaking (Offset)

Streaks in print are color density fluctuations or contrast variations, usually perpendicular to the print direction.

Pile Blocking

How to address blocking piles after press delivery (Offset)

Offset Ink Drying Issues

Abstract: While drying, conventional offset inks dry by evaporating volatile components (solvents) into the...

Ink Misting

Ink misting. Dirty printing presses caused by Ink-Aerosoles.

Piling

  Abstract Piling is an unwanted effect, where the pigments of the ink build-up negatively on the blankets. Serious...

Coating Chamber Leaking

How to address leaking/slinging coating units in industrial printing machinery.

Framing

Picture Framing. An printing issue were ink is getting transferred over non-printing area

Streaking (Offset)

Streaks in print are color density fluctuations or contrast variations, usually perpendicular to the print direction.

Offset Ink Drying Issues

Abstract: While drying, conventional offset inks dry by evaporating volatile components (solvents) into the...

Ink Misting

Ink misting. Dirty printing presses caused by Ink-Aerosoles.

Coating Chamber Leaking

How to address leaking/slinging coating units in industrial printing machinery.

Piling

  Abstract Piling is an unwanted effect, where the pigments of the ink build-up negatively on the blankets. Serious...

Framing

Picture Framing. An printing issue were ink is getting transferred over non-printing area

Pile Blocking

How to address blocking piles after press delivery (Offset)

Piling

  Abstract Piling is an unwanted effect, where the pigments of the ink build-up negatively on the blankets. Serious...

Coating Chamber Leaking

How to address leaking/slinging coating units in industrial printing machinery.

Framing

Picture Framing. An printing issue were ink is getting transferred over non-printing area

Streaking (Offset)

Streaks in print are color density fluctuations or contrast variations, usually perpendicular to the print direction.

Ink Misting

Ink misting. Dirty printing presses caused by Ink-Aerosoles.

Offset Ink Drying Issues

Abstract: While drying, conventional offset inks dry by evaporating volatile components (solvents) into the...

Pile Blocking

How to address blocking piles after press delivery (Offset)