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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.