Print Process Descriptions: Printing Industry Overview: Lithography

Fountain Solutions & Dampening System

• Direct Feed Continuous Integrated System
• Direct to Plate

Fountain solutions are applied to enhance the non-image areas ability to repel ink. Some newer fountain solutions have been developed with oxidizing chemicals which accelerate the setting and drying of inks and reduce the need for anti-set off sprays.

Anti-Set Off Sprays are fine corn starch powders sprayed on the sheets to prevent the ink from smearing and sticking onto the back of the top sheet as the printed material is stacked.

There are two common types of dampening systems; the direct feed continuous integrated system and direct to plate dampening system. Direct to plate dampening systems apply the fountain solution directly to the plate. Direct feed continuous integrations systems meter the fountain solution, which contains alcohol or an alcohol substitute, through the inking system. Direct feed can also act as a direct to plate dampening system and apply the fountain solution directly to the plate. This system generally uses less water, reduces makeready time and paper waste at start up.

The inking system, which has several rollers, is designed to work the ink so that it will be evenly distributed across the blanket. The rollers also aid in evaporating some of the water from the dampening system.

The fountain solution acts as the water solution for the hydrophilic process of lithographic printing. Fountain solution also helps to cool the press and facilitate the ink drying. Fountain solution is applied to the dampening roller to repel ink in the non-image areas of the plate.