Composition and Function of Fountain Solution (4)

Suitable for sheet-fed offset press Third, the amount of fountain solution control

1. Visual reflectance reflects the water film thickness

Specular reflection - too large

Reflective light is weak - water film is thin

Diffuse launch - too small

Water is too big: a, ink is light, gloss is poor, even if you increase the amount of ink, the ink does not deepen

b, Zhang water absorption, paper vertebral deformation in the paper

c. There is free water in the ink on the ink roller

d. Add new ink to ink fountain. New ink and old ink are difficult to mix

e, ink texture is rough

f, peeling, separation sound

The minimum water supply makes the plate will not appear dirty

The maximum water supply makes the ink on the ink roller free of free water droplets

The optimal amount of water supply is as low as possible if the printing plate is not dirty.

Attachment: a, if the requirement of low gloss gloss, increase the value of emulsification

b. If the printing is rough paper, increase the emulsification value, which is conducive to the transfer of ink

2, water film thickness measuring instrument

Basic principle: Infrared spectrum, in different thickness of aqueous solution, corresponding to different absorption spectra.