Solutions for Press Problems,
   
HeetSet Solution
 
PROBLEM CAUSE SOLUTION
TINTING/TONING:

Adhesion of ink to non-image area of the plate

1.Ink bleeding into fountain solution

2.Improper fountain solution concentration

3.Ink and dampening rollers set too tight to plate

4.Ink is taking on too much water and breaking down

5.Non-image area of plate has become sensitized and ink receptive.

1.Ensure that the correct level of alcohol(or substitute)is being used.

2.Check fountain solution by conductivity to ensure the correct dosage.

3.Reset to lighter pressure to avoid "grinding"pigment into the plate surface

4.Consult with ink and fountain solution suppliers.

5.Use plate cleaner,if toning returns remake plate and check fount strength.

INADEQUATE SETTING OF INK:

Ink remains tacky during press delivery and bindery operations,resulting in set-off,

marking or blocking

1.Dryer temperature too low for speed of web.

2.Excessive ink film thickness.

3.Poor ventilation at exit end of dryer,leaving solvent vapours near web

4.Chill system not working properly; ink resins are not setting hard enough

5.Paper is not porous enough or has too high water content.

6.Ink over-emulsifies with fountain solution.

7.Ink film is only set on the surface, and rewets after the chill rolls from trapped solvent.

8.Ink solvent is too slow evaporating at this dryer temperature.

1.Increase dryer temperature

2.Run less ink or use stronger ink

3.Increase velocity of air-knife scavenger at the dryer exit.

4.Lower chill roll temperature. Caution:watch for condensation.

5.Switch paper.

6.Adjust ink/water balance.

7.Reduce speed of press. Adjust oven temperature.

8.Consult inkmanufacturer.

HICKIES:

White spots surrounding a small spot.

1.Particles of dried ink.

2.Paper dust.

3.Dust from overhead objects(lights,ceiling…)

1.Clean rollers and inkfountain.

2.Consult paper supplier.

3.Clean all overhead objects in the work area.

MISTING/SPITTING:

Misting-fine droplets of ink thrown from ink rollers

Spitting-ink being thrown from rollers in filaments

1.Too much ink on rollers.

2.Ink too thin.

3.Press speed too high.

4.Improper ink/water balance.

5.Inking rollers are incorectly set or damaged.

6.Roller train is too hot.

1.Reduce ink film or use stronger ink.

2.Use ink with more body.Consult inksupplier.

3.Reduce speed of press.

4.Reduce ink setting and then water to lower point of ink/water balance.

5.Reset rollers and replace damaged rollers.

6.Increase flow of cooling water.

LOW LEVEL OF GLOSS: 1.Paper too ink absorbent.Paper surface very rough and grainy.Paper has poor gloss.

2.Dryer temperature too high.

3.Ink is over emulsified.

4.Ink film thickness too low.

5.Ink is too strong.

6.Excess alcohol.

1.Change paper.

2.Lower oven temperature and decrease press speed if necessary.

Obtain "low temperature" inks.

3.Verify fountain concentration and set water to minimum level.

4.Increase film thickness.

5.Reduce ink with varnish and run higher ink film thickness.

6.Reduce alcohol to 8%.

PILING:

Build-up of paper fibres or coating,or ink on rollers,blankets

or plates.

PAPER:see PICKING.

INK:

1.Ink is over-emulsified.

2.Ink is drying too fast on the blanket.

3.Blanket tack is too high.

4.Light coverage uses too little ink.

MECHANICAL:

1.Improper packing of cylinders or rollers not set correctly.

PAPER : see PICKING

INK :

1.Consult ink and fountain solution suppliers to reduce water take-up of ink.

2.Check press temperature or consult ink supplier.

3.Run more water or add non-piling additive.

4.Use take-off strips if possible, to increase ink consumption.

MECHANICAL :

1.Adjust settings.

PICKING:

Pulling fibres from uncoated or coating from coated papers.

1.Too much water reaching the paper.

2.Poor quality paper.

3.Impression cylinder pressure too high.

4.Blanket is too tacky.

5.Ink too tacky for paper .

1.Reduce dampener setting.

2.Change to a better quality paper with better pick resistance.

3.Reduce impression pressure.

4.Ensure that blanket is washed completely and not tacky after wash cycle.

5.Consult ink supplier.

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