Lags in Drying Time

A lag in drying time occurs when the ink dries too slowly in the stack. This may lead to the rubbing of colour off the print during post press or during transport.

The interaction between ink, additives, and dampening solution is usually to blame for lags in drying time. For example, should the pH-value of the dampening solution fall below 4.7, you can expect a longer drying time. Incorrectly dosed additives (drying accelerators), a stack temperature that is too low, or excessively emulsified ink also retards drying. In principle, the heavier the ink film, the slower the drying process.

Remedy:

• Optimal tuning between ink and paper (enquire with the manufacturer)
• Do not allow the pH-value of the dampening solution to cross below 4.7
• Avoid ink emulsification
• Only dose additives according to the manufacturer's instructions
• In cases of lower ink taking, also print ink stripes
• Avoid high ink film densities (employ ink reduction or high pigment inks)
• Use IR drying
• In order to rescue a print job, coat it with an oil or dispersion varnish