Category Archives: Energy Curable

Tinting

Fountain solution has wrong pH or conductivity

Check and correct fountain solution

Roller durometer or setting is wrong

Use proper roller and check setting

Prolonged use of detergent wash has occurred

Wash-up thoroughly and use hot water for final wash-up

Too much pressure exists between plate and blanket

Check and reset

Paper coatings and fountain solution are contaminating and glazing the ink rollers

Use lowest tack ink possible, lowest pressure setting, and properly balanced fountain solution

Plates are improperly exposed or developed

Consult your pre-press department

Body of ink is too soft

Consult your Sun Chemical representative

Temperature is too high in fountain solution pan and/or ink oscillator rollers

Adjust to recommended temperature range

Stripping

Rubber rollers are glazed

Normally this is gum glaze. Deglaze rollers with glaze remover, wash-up thoroughly, and use hot water for final wash-up

Fountain solution is too acidic

Adjust pH of fountain solution according to supplier specifications

Too much gum is in fountain solution

Do not add additional gum to fountain solution. Consult supplier if problem persists

Ink is too strong

Consult your Sun Chemical representative

Streaks in Print

Streaks appear about halfway around the cylinder in a printed image

Blanket is overpacked, causing a bump when striking the plate that jars form rollers. This creates a bounce and skid, producing a streak. Correct blanket packing

Streaks appear across the sheet one revolution back from the top of the plate

Ink form rollers are set too heavily to the plate. Set rollers to pressures specified by the press manufacturer

Slurring

Slippage between cylinders or press is occurring

Correct poor press conditions

Oil is on bearers

Correct poor press conditions

Cylinders are overpacked or under packed

Correct poor press conditions

Slurs that show a double dot in half-tones indicate improper press adjustment

Correct poor press conditions

Sharpness of Image

Body of ink is too low

Consult your Sun Chemical representative

Packing is incorrect on plate or blanket

Check and correct packing

Ink is too weak, or ink film is too thick, causing fill in

Replace with stronger ink and/or consult your Sun Chemical representative

Fountain solution is out of balance

Drain and replace with fresh fountain solution mixture

Scumming

Ink rollers are of the wrong durometer (too soft or too hard)

Check durometer, setting, and condition of ink rollers

Ink or dampener rollers are set too tight

Check and reset rollers

Blanket is overpacked or not tight

Correct packing and re-torque blanket

Prolonged use of oily wash-up solutions has occurred

Change to fresh wash-up solution

Plate is not properly sensitized

Consult your pre-press department

Fountain solution is out of balance

Drain pans and tanks. Refill with fountain solution of correct pH and conductivity

Ink film is too heavy

Change to a stronger ink and/or consult your Sun Chemical representative

Roller train temperature is too hot

Maintain 80°-85° F surface temperature on oscillators

Fountain solution is too hot in pans

Maintain fountain solution at 60°-65° F in press pans

Blanket is glazed

Remove glaze or change blanket

Poor Roller Transfer and / or Glazing

Rollers are improperly or inadequately cleaned

Thoroughly clean up with a good quality roller glaze remover. (To remove glaze, apply hot water to rollers after removing ink. This will remove gum glaze that is not soluble in standard wash-up solvents)

Rollers are improperly set; rollers are swollen or distorted

Adjust roller settings or check roller surface condition

Gum arabic and gum substitutes are in fountain solution; wetting agents have been used indiscriminately

Control use of additives and use proven fountain solution

Ink Piling

Ink becomes over emulsified. This causes the pigment to separate due to insufficient tack and viscosity

Run less fountain solution. Consult your Sun Chemical representative if problem persists. IPA concentration lower

Rollers are wrong durometer; rollers are improperly set; blanket is under packed or badly conditioned.

Use proper rollers and blankets. Check roller setting and blanket packing, or clean and condition

Ink is poorly ground

Consult your Sun Chemical representative

Ink roller train is too cool

Adjust oscillator surface temperature to 80°-85° F

Fountain solution pH and/or conductivity is incorrect

Check and adjust to supplier recommendations

Ink lacks sufficient lubrication or is unstable

Consult your Sun Chemical representative

Ink tack is too high

Reduce tack only enough to eliminate piling; excessively low tacks will cause other problems

UV inks are piling on down lane blankets when curing interstation

Impression is set too high, normally due to surface on uncoated paper causing poor solid ink lay; increased impression fills voids in substrate but causes piling. Can be treated as a result of poor cure due to old bulbs or dirty reflectors

UV/EB inks are piling on down lane blankets

Running too much water in previous units. Reduce ink/water setting in previous units

Substrate is dirty

Clean or change substrate

Mottling

Too much water is being used; inks are over emulsified

Reduce water; adjust ink/water balance

Too much water is present in prior unit; water is left on web or sheet

Reduce water in prior unit

Stock is weak, or paper coating is too soft

Reduce ink with proper reducer

Excessive pressure exists between blanket and stock

Reduce pressure to press manufacturer’s specifications

Blanket is too hard

Change to softer blanket

Ink is too strong; insufficient ink is being carried to the plate

Weaken ink strength by adding transparent white

Substrate is poor

Change to another substrate or lot of same material