The composition and role of the fountain solution summary (c)

Clean the printing plate and ink balance

The water has big “white spots”, and there are water traces in the field. It is weak, the ink is dark, the paper absorbs water, and it becomes open. Overprinting is not allowed.

Small water, dirty plates

First, based on the phase volume of the ink and water balance

Under the fixed process conditions, the amount of water supplied by the ink is adjusted so that the mixing and emulsification of the ink is within the allowable range of the process.

(15%<Emulsification value W/O<26%=

Attachment: Emulsification value = water/water + ink

Second, the balance of water and ink based on the theory of surface excess free energy

From the surface excess free energy of the interface between ink and water, find an energy relationship that does not invade each other.

Surface tension of fountain solution > Surface tension of ink

The fountain solution surface tension = 4.0~5.0*10-2N/m

Control of fountain solution usage

First, the fountain solution consumption

1, emulsified with the ink

2, in the air evaporation

3, directly absorbed by the paper

4, dripping at both ends of the drum

Second, the factors affecting the amount of fountain solution

1, different types of fountain solution used in different amounts

Dirty ---- Minimum usage

Printed product - The amount of water supply is too large and the ink is free from "waterdrops"

2, the text area and ink thickness requirements

The amount of ink supplied is large, and the amount of water supply is large, and vice versa.

Daimo Dashui

3, ink properties

Different kinds of ink

Pigment acid viscosity

4, printing speed

The amount of fountain solution used increases with increasing printing speed

5, temperature

High ambient temperature, large air flow, increased water evaporation, and increased water supply

Temperature changes throughout the ink system

6, additives

Dilute, remover, desiccant

7, plate sand

Sand particle size

Coarse --- large amount of water, mainly used for web offset press

Fine --- small amount of water