TECHNICAL SUPPORT (OFFSET INK, COATINGS, UV)

Problem

Symptom

Solution

Constant film weight cannot be maintained on print.
Ink does not follow duct rollers.

1. Ensure there is sufficient ink in the ink duct.
2. Add AS/8658 Flow Improver to the ink. (Max 5%)

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

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) Eg. Mattking / Speedset. 
4. Use BS/8455 O.P. Medium to save printed sheets.

Halftone dots increase in size causing the printed matter to lack sharpness. 

1. Reduce ink release. 
2. Check reproduction process/ plate/ blanket. 
3. Ensure proper ink-water balance.
4. Check pressure between form roller to plate to blanket to paper.
5. Use stronger ink – Eg. Mattking / Speedset. 
6. Add AS/8726 Synthetic Medium. (Max 5%)

Light tint appears on unprinted parts of stock and water marks spoil printed areas. 

1. Maintain proper ink-water balance. 
2. Clean/check plate, correct if necessary. 
3. Ensure fountain pH is between 4.8 & 5.5.  
4. Add AS/8953 Thickening Powder to improve water resistance. (Max 2%)

Print changes strength or colour with time. 

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

Less gloss/reflection from printed image.

1. Use smoother paper. 
2. Reduce fountain solution feed. 
3. Increase Ink film thickness slightly.
4. Use Glossy ink – Eg. Boss/Mattking/Speedset/Pearl

Blemishes in the Printed Ink Film, especially for Solid Image Area.

1. Ensure there is no skin while putting ink into ink duct.
2. Clean 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.

More ink is consumed per impression than normal. 

1. Adjust colour densities to optimum with satisfactory print quality. 
2. Maintain proper ink-water balance.
3. Use stronger ink – Eg. Mattking / Speedset. 

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

1. Use stronger ink with lower release.
2. Check roller settings.
3. Release optimum fountain solution. 
4. Reduce the printing speed.
5. Add AS/8425 Q.S.Tack Reducer. (Max 5%)

Particles torn from papers, paper coating scattered at irregular places. 

1. Use paper having good pick strength. 
2. Use less tacky blanket.
3. Check print pressure.
4. Reduce machine speed.
5. Add AS/8425 Q.S.Tack Reducer. (Max 5%)

Loss of image area meaning successive impression becomes weaker and weaker.
Especially common in long run jobs.

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 ink manufacturer to check grinding.

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

1. Reduce damping solution feed. 
2. Ensure fountain pH is between 4.8 & 5.5.  
3. Clean the rollers and copperize if reqd.
4. Add AS/8953 Thickening Powder to ink. (Max 2%)

Printed Ink film appears dry but gets smudged/ transferred when rubbed. 

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 BS/8455 O.P. Medium.

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

1. Ensure fountain pH is between 4.8 & 5.5. 
2. Check plate wear-off. 
3. Use stronger ink and run with reduced release.
4. Correct Inkers and Dampers setting.
5. Add AS/8726 Synthetic Medium. (Max 5%)

Ink marks appear on the back of the next sheet in the delivery pile. 

1. Reduce Ink release. 
2. Use Higher Quality Ink (Stronger and Fast-setting) Eg. Mattking / Speedset. 
3. Reduce size of stacks. 
4. Use S/5400 Unispray Powder in multicolour printing.
5. Add U/214 Speedofix Liquid Drier. (Max 2%)

Ink film remains wet or tacky to the touch. 

1. Avoid addition of any non-drying compounds. 
2. Avoid using highly acidic paper. 
3. Ensure fountain pH is between 4.8 to 5.5
4. Avoid excess fountain solution onto the plate. 
5. Add U/202 Liquid Drier. (Max 2%)
6. Add U/223 Lithodri Drying Stimulator to fount soln.

Subsequent colours on multicolour job do not transfer properly, resulting in poor Colour balance. 

1. Check temperature of the ink roller. 
2. Make sure inks are printed in decreasing tack order.
3. Check ink release of subsequent colours.
4. Maintain proper ink-water balance.
5. Check the strength and viscosity of ink by consulting ink manufacturer. 
6. Add AS/8425 Q.S. Tack Reducer in subsequent colours. (Max 5%)