Graphic Design & Printing TechnologyFountain roller:- Fountain roller is the roller that is placed inside the ink
fountain. It transfers ink from the fountain to the ductor roller.
Dampening system
A layer of moisture must be placed over the non image area before the plate is
inked. The dampening system accomplishes this by moistening the plate
consistantly through out the press run. The fountain roller rotates in a pan
containing the fountain solution. It transfers a thin film of fountain solution
either to the ductor roller or directly to the form rollers.
Offset press dampening systems are classified into three types - Intermittent,
Continuous and Integrated.
Intermittent system (Conventional dampening system) :-It is similar in design
to the inking system on an offset press. The system uses oscillator rollers,
form rollers, a ductor roller and a fountain roller. The dampening system uses
fewer rollers than the inking system does because fountain solution is more
fluid than the ink and does not need to be worked to the same degree.
A common problem with an intermittent system is their inability to quickly
adjust the level of solution on the plate.
Continuous dampening system:- They do not use ductor roller to transfer
fountain solution from the pan. This system use a metering roller to move the
solution to a transfer roller. The metering roller is usually made of or covered
with rubber and serves the same purpose as the fountain roller in an intermittent
system. The transfer roller is a hard chrome covered roller. The biggest
advantage of using continuous system is that it allows the operator to quickly
make adjustments and see immediate results. Continuous dampening system
are often referred to as alcohol dampening system because alcohol was
commonly used in the fountain solution.
Integrated dampening system:- This type, of dampening system link the
dampening rollers and the inking rollers to the ink fountain. The fountain
solution and the ink are fed to the plate from the same set of form rollers. The
fountain solution is distributed, not only to the rollers in the dampening system
but also to sum of the ink rollers. Since the fountain solution repels the ink it
can ride on the ink to the plate. This type of system is also referred to as
combined dampening system or combination dampening system. Improper
formulation of fountain solution in the system may cause emusification
problems.