Technical PresentationOn

Fountain Solution & Its Functions

June 2013

Presented By:- Neeraj Kumar

Co-Presenter :- Mr. Sharat Babu

Expert :- Mr. Junji Uchimura

What is Fountain Solution

Supply a film of Fountain Solution

Desensitizing the non image areas

Cleaning

Spreading of Solution

Lubrication

Maintaining Proper Emulsification

Plates

Plate Anatomy

Aluminium Base

Graining

Anodic LayerCoating

Vaccum Assist Layer

Aluminium GrainedSurface

AnodisedSurface

UnexposedCoating

ExposedCoating

Vacuum Assist Layer

Developed Image

Plates Cont….

Ingredients of Fountain Solution

• Water Soluble Gum

• A pH Buffer System

• Desensitizing Salts

• Acids & Their Salts

• Wetting Agent

• Non Piling & Lubricating Additives

• Emulsion Control Agents

• Biocides

• De-foaming Agents

• Dyes

Surface Tension & Its Significance

Contact angleDegree of

wetting

Strength of:

Solid/liquid

interactions

Liquid/liquid

interactions

θ = 0 Perfect wetting strong weak

0 < θ < 90° high wettabilitystrong strong

weak weak

90° ≤ θ < 180° low wettability weak strong

θ = 180°perfectly

non-wettingweak strong

pH & Conductivity

What is the pH Scale?

•Each hole number on the pH scale represents a tenfoldchange in acidity or alkalinity.

•A solution at (pH 5.0 is 10 times more acidic than a pH6.0).

•A solution at (pH 9.0 is 10 times more alkaline than apH 8.0) and a solution at (pH 10.0 is 100 times morealkaline than a pH 8.0).

What is Conductivity?

•Conductivity is the ability to transmit or conduct anelectrical charge.

•The degree of conductivity is determined by thenumber of ions present as a result of minerals or othercompounds in the water.

•The higher the concentration of ions, the higher thedegree of conductivity(and usually the harder thewater).

Importance of Water

How Important is the Water Source?

pH

1__Acidic______4.5_ 5.5___7___8________Alkaline_____14

-----------------Printing-----Neutral----------------------------

Conductivity

0_________200_________500_________700__________1000

Soft --------------------------Medium--------------------Hard

Components of Water

Conductivity (Flow of Minerals)

Total Hardness (Calcium/Magnesium etc..)

Total Alkalinity (Carbonates & Bi-Carbonates)

Corrosive ingredients ( Chlorides)

pH Cond. Total

Hardness

Total

Alkalinity

Chlorides

Standard

7.0 –8.0

300–360 mS

< 150

ppm

<70 ppm

<25 ppm

Effects of Hard Water

What harm hard water do?

Forms soaps causing roller stripping, halftone fill-in. Calcium & Magnesium ions cause glaze & increase of shore-hardness.

What harm Chlorides do?

Chlorides are highly Corrosive, Cause Metal Corrosion.

Chlorides level above 25 ppm are harmful for metal parts.

What harm Alkalinity do?

Alkalinity is more important than water hardness, excessive levels of alkalinity shift pH towards neutral.

Raw water treatment options

Reverse Osmosis (RO)

Demineralization(DM)

Water

•Reverse Osmosis water.

The best method of water purification. In this processthe water is filtered through a membrance to remove mostof the positive and negative ions, un-ionized dissolvedsolids(sugars), suspended matter, and bacteria leavingonly pure water.

Sometimes referred to as “RO water”.

Reverse Osmosis

De-ionization, or the demineralization process.

• A complex chemical process that uses two ionexchange resins to remove minerals from water. Thecost of this method is considerably less than the costof producing distilled water.

Distilled water.

• Produced in a laboratory by boiling ordinary tapwater in a water still. The steam that rises from theboiling water is almost free of the mineral matterpresent in the tap water. The steam is fed throughcondenser coils where it is converted into liquid,distilled water. Some fountain solutions do not workwell with distilled water.

De-ionization, or the demineralization process.

Soft water

• Always corrodes

• Forms emulsion with ink with high reluctance

• Remove all alkalinity giving elements

• Then add only that much that are required for printing consistency (150 to 180 ppm)

Features :

Keeps the salts in water in dissolved form

Effectively controls the growth of bacteria and other micro-organisms

Neutralises high alkalinity

Benefits :

Reduced maintenance of rollers and blankets

Reduced instances of roller stripping

Longer life of mixed fountain solution in the circulation system

Minimum fount dosing and pH stability

Fount Additive Functions on Raw Water

Features :

Promotes ink receptivity of the plate coating

Protects the coating against harmful water-salts

Prevents ink pile-up on the plate & blanket

Benefits :

Longer run-length

High ink density with lower ink consumption

Instant start-up ink roll-up with lower paper waste

Faithful halftone resolution with low dot gain

Smooth solids & brilliant colours

Reduction in plate & blanket wash-up downtime

Fount Additive Functions on Plate Image Area

Plate Non-Image Area

Features :

Protects the porous anodic layer against attack from harmful water salts

Enhances the water receptivity of non-image areas

Keeps the anodic layer pores continuously open

Minimises deposition & ensures instant clean-up of ink & grit during re-start-ups

Benefits :

Zero tinting or scumming

Instant clean start-ups with lower print waste

Fount Additive Functions on Non Image Area

Dampening System

Features :

Ensures compatibility with various types of dampening systems, conventional as well as contemporary

Ensures optimum damp throughput with covered/bare back/non-contact system designs

Benefits :

Prevent intermittent scum by providing a thin continuous and even spread of dampening film across and around the cylinder

Eliminate the need for frequent feed adjustments at varying machine speeds

Prevent ink accumulation on rider rollers and foaming in the circulation System

Fount Additive Functions on Dampening System

Fount Additive Functions on IPA

IPA (Isopropanol)

Features :

Formulations tailor-made to eliminate / reduce the level of alcohol usage

Benefits :

Reduced cost without compromising quality

Pressroom free from unhealthy alcohol vapours

Safer environment; lower VOC emission and effluents

Why replace alcohol ?

Hazards to environment and health

Flammable and unsafe

Risk of emulsification and reduced ink

density

High evaporation loss

High cost-in-use

Fount Additive Functions on Machine Parts

Machine Parts

Features :

Adheres to corrosion limits set by machinery manufacturers

Provides a lubricating film at the contact point of the plate with inkers, dampeners & blanket

Benefits :

Compliance to machine manufacturer’s warranty with lower replacement cost

Reduced friction means reduced plate wear and elimination of variation in print quality

Reduced rate of paper lint piling and instances of blanket cleaning

Ink

Features :

Stable emulsion

Formulations tailor-made for UV / Metallic and special application

Benefits :

Zero emulsification and ink bleeding problems

Consistent quality for special applications

Fount Additive Functions on Ink

Paper / Substrate

Features :

Minimum interference of substrate characteristics

Minimum Attack on Paper Coating

Benefits :

Optimum print quality

Less web breaks/Blanket Cleaning.

Fount Additive Functions on Substrate

Fountain solution problems

Possible problems when too much Fount concentrate is used?

Over Emulsification (especially reds and blues).

Background tinting.

Poor ink-acceptance in image area, resulting in mottling or blinding of the plate.

Premature plate wear from lack of ink lubrication.

Slow drying of inks and possibly, of chalking.

Stripping of the ink rollers.

Fountain solution problems cont…

Filling in of reverses and halftone screens.

Scumming.

Tinting.

Inadequate gum will leave plate non-image

areas unprotected.

Lack of anti-corrosive ingredients will lead

to premature plate wear.

What happens when too little concentrate is used?

Press Care Chemicals

•Press Wash

•De-glazer

Roller Surface

• Roller surface is uneven full of fingers.

• Rough surface carries ink & water.

• Better ink & water emulsion due to constant

agitation.

Roller GlazeGlaze is caused by the buildup of particles in the mountains and valleys of the roller surface. This gives the roller a smooth surface and makes it unable to convey ink or water, which results in a long list of printing problems.

Clean Roller Surface Glazed Roller Surface

NAP of a Glazed Roller

• Water-soluble particles (gums, coatings, dust),

• Solvent-soluble particles (inks, etc.)

• Insoluble residue (mineral deposits, clays, soap deposits).

How to Remove Glaze• Step 1: Use a water miscible wash (solvent mixed with water) to remove both

the solvent-soluble and water-soluble particles

• Step 2: Use a non-grit roller paste to remove the insoluble particles

• Hardening Rubber Roller & Its Effects

• Cracked Rubber Roller & Its Effects

• Swollen/Uneven Rubber Roller & Its Effects.

• Calcified Rubber Roller & Its Effects

Effects on Rollers without Cleaners

Hardened Rubber Roller & Blankets

Effects:-

•Inking Rollers don’t get properly cleaned

•Inking rollers get higher m/c speed

•Sudden ink contamination

•Frequently scumming at the gripper

•Sheets variation in the multiple ups

•Sticky ink deposits in the non image areas of blankets

•Uneven dampening supply to the plate, increase in water feed

Cracked Rubber Roller

Effects:-

•Jumping of Rollers at higher m/c speed

•Filled up fine halftones

•Premature plate wear with typical pattern

•Inking units don’t get properly cleaned

Swollen/Uneven Inking Roller

Effects:-

•Uneven Ink Distribution

•Premature plate wear

•High rate of emulsification

•Poor drying

Calcified Roller

Effects:-

•Roller Stripping

•Uneven Dampening Supply to the plate

•Calcium is water friendly, colorless & odorless, can’t be made out whether calcified.

•Normally when printer states that I need more water to release is first indication of calcification.