Trouble Shooting Support for Offset Inks, UV Curing Inks and Coatings

Backing – Constant film weight be maintained on print, ink does not follow duct rollers.

• SOLUTION:

1. Ensure there is sufficient ink in the ink duct
2. Add flow improving varnish to the ink max 5%

Chalking – Ink pigment does not bind to the stock and comes off by mere rubbing.

• SOLUTION:

1. Use less absorbent paper
2. Ensure fountain pH is between 4.8 to 5.5
3. Use higher quality ink (stronger and fast setting)
4. Use O.P. varnish to save printed sheets

Dot Gain/Muddy Halftones – Halftone dots increase in size causing the printed matter to lack sharpness.

• SOLUTION:

1. Reduce ink release
2. Check reproduction process/plate/blanket
3. Ensure proper ink-water balance
4. Check pressure between from roller to plate to blanket to paper
5. Use stronger ink

Emulsification/Tinting – Light tint appears on un-printed parts of stock and water marks spoil printed areas.

• SOLUTION:

1. Maintain proper ink-water balance
2. Clean/check plate, correct if necessary
3. Ensure fountain pH is between 4.8 to 5.5 

Fading – Print changes strength or color with time.

• SOLUTION:

1. Check paper stock
2. Use Light-Fast Inks in case of outdoor exposure

Gloss(Low) – Less gloss/reflection from printed image.

• SOLUTION:

1. Use smoother paper
2. Reduce fountain solution feed
3. Increase ink film thickness slightly
4. Use glossy ink

Hickies – Blemishes in the printed ink film, specially for solid image area.

• SOLUTION:

1. Ensure there is no skin while putting ink into ink duct
2. Clear rollers and blankets to remove dried ink
3. Inspect press room and press for cleanliness to avoid dust/contamination
4. Use paper having good pick strength to avoid fluffing

Mileage – More ink is consumed per impression than normal.

• SOLUTION:

1. Adjust color densities to optimum with satisfactory print quality
2. Maintain proper ink water balance
3. Use stronger ink

Misting/Flying – At high machine speed, a spray/fog/mist is visible in the air which finally covers entire parts of the press.

• SOLUTION:

1. Use stronger ink with lower release
2. Check roller settings
3. Release optimum fountain solution
4. Reduce the printing speed
5. Add Tack Reducer at Max 5%

Picking of Paper – Particles torn from papers, paper coating, scattered at irregular places.

• SOLUTION:

1. Use paper having good pick strength
2. Use less tacky blanket
3. Check print pressure
4. Reduce machine speed
5. Add Tack Reducer at Max 5%

Plate Wear Off – Loss image area meaning successive impression becomes weaker and weaker, especially common in long run jobs.

• SOLUTION:

1. Re-adjust the pressure of ink form roller and damping form roller
2. Check/reduce plate to blanket pressure
3. Check quality of plate
4. Ensure fountain pH is between 4.8 to 5.5
5. Consult the ink manufacturer to check grinding

Roller Stripping – Steel rollers do not accept ink and remain blank at certain areas.

• SOLUTION:

1. Reduce damping solution feed
2. Ensure fountain pH is between 4.8 to 5.5
3. Clean the rollers and copperize if required

Rub Resistance/Scuff Resistance(Poor) – Printed ink film appears dry but gets smudged/transferred when rubbed.

• SOLUTION:

1. Reduce fountain solution feed
2. Ensure fountain pH is between 4.8 to 5.5
3. Use smoother paper
4. Print with optimum ink release
5. Consult ink manufacturer
6. Use OP varnish

Scumming – Ink patches showing on non-image areas on the print.

• SOLUTION:

1. Ensure fountain pH is between 4.8 to 5.5
2. Check plate wear off
3. Use stronger ink and run with reduced release
4. Correct inkers and dampers setting

Set-off – Ink marks appear on the back of the next sheet in the delivery file.

• SOLUTION:

1. Reduce ink release
2. Use high quality ink (Stronger and fast setting)
3. Reduce size of stacks
4. Use Anti-setoff powder in multi color printing
5. Add SN 8193 Liquid Drier at Max 2%

Slow Drying – Ink film remains wet or tacky to the touch.

• SOLUTION:

1. Avoid addition of any non-drying compounds
2. Avoid using highly acidic paper
3. Ensure fountain pH is 4.8 to 5.5
4. Avoid Excess fountain solution unto the plate
5. Add SN 8193 Liquid drier at max 2%

Trapping – Subsequent colors on multi colors job do not transfer properly, resulting in poor color balance.

• SOLUTION:

1. Check temperature of the ink rollers
2. Make sure inks are printed in decreasing tack order
3. Check ink release of subsequent colors
4. Maintain proper ink water balance
5. Check the strength and viscosity of ink by consulting ink manufacturer
6. Add Tack Reducer in subsequent colors at max 5%