- Picking
- Deformation in the stack
- Double print
Abnormal pressure force and dots blurred. - Binding of the plate
Deterioration of the printing areas and/or graining areas (non- printing areas). - Scumming Blocking
- Out of register prints
- Set-off
- Incorrect drying
- Hickies
- Creasing
Deformation of the substrate, mainly at the tail end. - Powdering
The ink solids remain on the surface.
- Poor trapping
Ability of one ink to be accepted by another when it is not yet dry (this phenomenon only applies to wet-on-wet printing). - Curling
Excessive deformation of the printed material in the stack (excessive curling beyond 4cm/m).
- Mottling
Irregular appearance (mainly on solid print areas). - Linting
Loose paper accumulated on the blanket.
- Piling / Buildup
Ink build up on image areas of the blanket - Guttering
- Phantom effect
Reappearance of the previous print run or the print run underway but out of shift.
Probable causes and remedies
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Cause
|
Paper too fragile (poor coating or poor structure).
|
|
Remedie
|
Change the paper, dilute the ink or use a more suitable ink (less tack). Add Anti Tack Compound (3 % max.) or Arctic Thinner 501 (3% max.).
|
|
Cause
|
Restarting after a prolonged press stoppage.
|
|
Remedie
|
Spray Rototack start-up aerosol over the rollers.
Apply a little thinner (Artic Thinner 501) onto the rollers. Clean the rollers. Clean the blankets. |
|
Cause
|
Print shop temperature too low.
|
|
Remedie
|
Dilute the ink before restarting printing. .
|
|
Cause
|
Excessive dampening.
|
|
Remedie
|
Reduce the dampening.
|
|
Cause
|
Excessive blanket / paper pressure.
|
|
Remedie
|
Check the blanket / cylinder pressure, the counter pressure and the cylinder coverings.
|
|
Cause
|
Blanket has too much “affinity” for the ink.
|
|
Remedie
|
Apply talc on the blankets.
|
|
Cause
|
Substrate stored incorrectly.
|
|
Remedie
|
Before printing: store in the original packaging at a temperature of around 20°C and a relative humidity of 60 %, for a period determined by the temperature in relation to the volume of the stack.
During printing: between runs, do not hesitate to cover pallets to avoid deformation phenomena. |
|
Cause
|
Excess or irregular use of anti set-off powder.
|
|
Remedie
|
Adapt the quantity of anti set-off powder and its particle size to the job in hand. Clean the powder spray nozzles.
|
|
Cause
|
Excess water, principally on the paper edges.
|
|
Remedie
|
Reduce or adjust the uniformity of the dampening.
|
|
Cause
|
Substrate deformed before printing.
|
|
Remedie
|
Change the substrate.
Avoid important relative humidity and temperature variations between the storage and printing areas. Place the paper in the print shop several hours before printing. |
|
Cause
|
Blanket not tight enough.
|
|
Remedie
|
Retighten the blanket.
|
|
Cause
|
Excess pressure.
|
|
Remedie
|
Check the cylinder coverings.
|
|
Cause
|
Slack impression cylinder or transfer cylinder clips.
|
|
Remedie
|
Adjust the clips (wear on the heels of the clips).
|
|
Cause
|
Tack of the ink too high.
|
|
Remedie
|
Add Anti Tack Compound (3% max.) or Arctic Thinner 501 (3% max.) to the ink.
|
4. Binding of the plate, deterioration of the printing areas and/or graining areas (non- printing areas).
(back to incidents)
(back to incidents)
|
Cause
|
Abrasive particles from the paper coating deposited on the blankets.
|
|
Remedie
|
Pre-lacquer the substrate. If possible, place the first group under pressure only with the dampening.
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|
Cause
|
Pre-sensitised plate exposed too long to light.
|
|
Remedie
|
Rework the plate. Protect the plate during print runs and apply gum during press stoppages.
|
|
Cause
|
Quality of the plate unsuited to the length of the print run.
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|
Remedie
|
Properly oven treat the plates.
|
|
Cause
|
Form rollers incorrectly adjusted (pressure too high).
|
|
Remedie
|
Adjust the roller settings.
|
|
Cause
|
Excess plate cylinder / blanket cylinder pressure.
|
|
Remedie
|
Adjust the pressures. Check the cylinder coverings.
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|
Cause
|
Excessive hardness of rollers.
|
|
Remedie
|
Deglaze the rollers with Roline Arctic Deglazer or change them.
|
|
Cause
|
Abnormal movement of form rollers (with certain presses, equipped with form roller movement, it is recommended to use special high quality or oven treated plates).
|
|
Remedie
|
Change the bushes or rollers.
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|
Cause
|
Abusive use of hicky removal systems (delta effect).
|
|
Remedie
|
Use the system sparingly (less than 1 minute).
|
|
Cause
|
Water too acid.
|
|
Remedie
|
Adjust the pH to obtain a fount solution within the norms.
|
|
Cause
|
Water too hard.
|
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Remedie
|
Check the water hardness.
|
|
Cause
|
Paper surfacing or coating fragile. Incorrect ratio between surface tension of fount solution / surface energy of plate
(ST < SE). |
|
Remedie
|
Improve the transfer of the fount solution by checking its dosage and, if necessary, add a transfer improving agent. Rework the plate.
|
|
Cause
|
Paper too alkaline.
|
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Remedie
|
Readjust the water / ink balance.
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|
Cause
|
Oxidation of the plate due to insufficient or incorrect gumming.
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Remedie
|
Clean the plate with a de-oxidising solution followed by light gumming.
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|
Cause
|
Dampeners clogged up.
|
|
Remedie
|
Check / clean the dampening rollers and the dosing units.
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|
Cause
|
Partial swelling of the blanket due to excessive use of deglazer.
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Remedie
|
Change the blanket.
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|
Cause
|
Temperature too high in the inking rollers (ink becomesmore fluid).
|
|
Remedie
|
Reduce the temperature and the print speed, change the ink and restart the print run.
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|
Cause
|
Excessive inking.
|
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Remedie
|
Reduce inking. Use an ink with higher colour strength.
|
|
Cause
|
Tack of the ink too low.
|
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Remedie
|
Use a more tacky ink.
|
|
Cause
|
Ink too diluted.
|
|
Remedie
|
Open a new tin of ink.
|
|
Cause
|
Ink too siccative.
|
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Remedie
|
Use a less siccative ink.
|
|
Cause
|
Poor dimensional stability of the paper (paper fibre in wrong direction) and excess water.
|
|
Remedie
|
Always print the substrate with the paper fibres parallel to the cylinders.
|
|
Cause
|
Blanket tension incorrect.
|
|
Remedie
|
Retighten.
|
|
Cause
|
Unsuitable cylinder coverings.
|
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Remedie
|
Adapt the cylinder coverings to rectify them if possible.
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|
Cause
|
Clips loose due to incorrect adjustment and / or tacky ink.
|
|
Remedie
|
Adjust the clips.
|
|
Cause
|
Paper deformed after several print runs and / or high inking level.
|
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Remedie
|
Reduce inking.
|
|
Cause
|
Optical Density too high, out of standard.
|
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Remedie
|
Print using the Brunner standard, for example, or print using two printing units. Reduce inking.
|
|
Cause
|
Poor ink distribution.
|
|
Remedie
|
Adjust the form rollers of the printing unit.
|
|
Cause
|
Incorrect Dampening.
|
|
Remedie
|
Adjust the fount solution. > See « The fount solution ».
|
|
Cause
|
Excess water.
|
|
Remedie
|
Adjust the water / ink balance.
|
|
Cause
|
Deformation of the stack due to heavy loads. Stack toohigh.
|
|
Remedie
|
Adapt the height of the stack according to the inking level and paper weight. Do not stack up pallets.
|
|
Cause
|
Not enough anti set-off powder.
|
|
Remedie
|
Adjust the amount of anti set-off powder.
|
|
Cause
|
Particle size of the anti set-off powder not adapted tothe substrate.
|
|
Remedie
|
Adapt the particle size to the weight of the paper / cardboard. Use Arctic Vanesse or Arctic Vanesse 15μm anti set-off powders. Take account of post printing operations (varnishing, laminating).
|
|
Cause
|
IR lamps at incorrect temperature.
|
|
Remedie
|
Adjust the temperature of the IR lamps as a function of the prin- ting speed, substrate grammage and whether printing on both sides. Recommended temperatures:
Top side: maximum 35°C Reverse side: maximum 30°C. |
|
Cause
|
Magnetisation of the paper.
|
|
Remedie
|
Use a suitable anti-static system. Properly earth the press. Humidify the print shop.
|
|
Cause
|
Handling of the stack after printing.
|
|
Remède
|
Descend the loader slowly. Handle the stacks carefully.
|
|
Cause
|
Unsuitable ink.
|
|
Remedie
|
Change the ink / substrate. Consult the supplier.
|
|
Cause
|
Ink too emulsified.
|
|
Remedie
|
Wash the printing unit and re-start with minimum dampening.
|
|
Cause
|
Substrate too acid (destabilisation of the water / ink balance).
|
|
Remedie
|
Check the pH of the fount solution. Change the substrate.
|
|
Cause
|
Fount solution too acid.
|
|
Remedie
|
Check and adjust the fount solution > See « The fount solution ».
|
|
Cause
|
Excessive inking.
|
|
Remedie
|
Reduce the amount of inking.
|
|
Cause
|
Excessive dampening.
|
|
Remedie
|
Reduce the amount of dampening. If necessary, clean the inking train so as to completely eliminate the emulsion and restart with less dampening. Check the pressure of the dampening rollers.
|
|
Cause
|
Wrapping or film covering too rapid (air oxidation ofthe ink film insufficient).
|
|
Remedie
|
Allow inks to dry completely before wrapping or covering in film.
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|
Cause
|
Ink too emulsified.
|
|
Remedie
|
Find the correct ink / water balance.
|
|
Cause
|
Ink does not dry correctly.
|
|
Remedie
|
Add Triple Drying Agent (1 % max. since too much drying agent can inhibit drying).
|
|
Cause
|
Ink not adapted to the substrate
|
|
Remedie
|
Consult the supplier.
|
|
Cause
|
Poor quality paper (linting, coating lift off).
|
|
Remedie
|
Change the paper or reduce the tack of the ink with Anti Tack Compound (3% max.). Carry out a run without inking.
|
|
Cause
|
Accumulation of ink on the dampeners and / or thedampener form rollers.
|
|
Remedie
|
Wash the dampening rollers. Prevention: replace the first form roller with an anti-hicky roller. If re-guillotining the paper, square it up well, and avoid making a reject cut.
|
|
Cause
|
Ink used from opened or incorrectly protectedcontainers.
|
|
Remedie
|
Protect opened tins correctly with cellophane or by spraying Anti-drying A11 and remove the surface skin.
|
|
Cause
|
Skin on the ink when container opened.
|
|
Remedie
|
Change the container of ink.
|
|
Cause
|
Paper wrapped before printing.Excess paper hygrometry.
|
|
Remedie
|
Check the storage of the paper. Store the paper in the print shop before printing.
|
|
Cause
|
Deformation of the paper on first print run due to toomuch inking or an ink with too high tack.
|
|
Remedie
|
Reduce the tack of the ink during the second print run. Use Anti Tack Compound or Arctic Thinner 501.
|
|
Cause
|
Clips incorrectly adjusted on the margin or wheelsincorrectly adjusted (pressure too high).
|
|
Remedie
|
Adjust the clip settings to regular pressures. Reduce the wheel pressure settings.
|
|
Cause
|
Blanket not sufficiently tight.
|
|
Remedie
|
Retighten the blanket.
|
|
Cause
|
Paper too porous, causing the ink binder to separatefrom the pigment.
|
|
Remedie
|
Apply a primer coat.
|
|
Cause
|
Ink viscosity too low.
|
|
Remedie
|
Use a higher viscosity ink.
|
|
Cause
|
Drying of ink too slow.
|
|
Remedie
|
Use a more siccative ink. Consult the supplier.
|
|
Cause
|
Dampening water too acid, leading to longer dryingtimes.
|
|
Remedie
|
Adjust the fount solution. To mask the phenomenon, apply an overprint varnish.
|
12. Poor trapping, ability of one ink to be accepted by another when it is not yet dry (this phenomenon only applies to wet-on-wet printing).
(back to incidents)
(back to incidents)
|
Cause
|
Unsuitable colour sequence.
|
|
Remedie
|
Adjust the colour sequence: Print low colour deposits before high colour deposits (e.g. Violet = 75 % Red and 100 % Blue ⇒ Print the Red first). In the case of poor trapping, dilute the second colour (e.g. Violet = 100 % Red and 100 % Blue ⇒ Dilute the Blue with a suitable thinner).
|
13. Curling, excessive deformation of the printed material in the stack (excessive curling beyond 4cm/m).
|
Cause
|
Problem with the paper.Curling of the sheet parallel or perpendicular to thedirection of the press (central region of the parent roll,foudrinier table, dryer).
|
|
Remedie
|
Change the paper.
|
|
Cause
|
Hygrometry too high or important change in the hygrometry.
|
|
Remedie
|
Check the storage conditions.
|
|
Cause
|
Unsuitable blanket hardness.
|
|
Remedie
|
Use a blanket with a harder surface.
|
|
Cause
|
Excessive dampening.
|
|
Remedie
|
Reduce the dampening.
|
|
Cause
|
Ink too tacky.
|
|
Remedie
|
Reduce the tack with Anti Tack Compound (3 % max.). When printing large solid areas, print a light screen first (base print), which then allows the thickness of the ink film to be reduced on a second print run.
|
|
Cause
|
Paper has irregular smoothness.
|
|
Remedie
|
Change the paper. Change the ink.
|
|
Cause
|
Excess dampening, which has the effect of reducingthe tack.
|
|
Remedie
|
Adjust the dampening to the minimum.
|
|
Cause
|
Ink too emulsified.
|
|
Remedie
|
Change the ink.
|
|
Cause
|
Lack of pressure (piling).
|
|
Remedie
|
Adjust the pressure settings.
|
|
Cause
|
Ink from previous prints deposited on the blanket.
|
|
Remedie
|
Dilute the ink of the previous printing units that are being trans- ferred.
|
|
Cause
|
Binding or surfacing of the sheet of paper insufficient.
|
|
Remedie
|
Print a solid print area with transparent white ink without dam- pening. Carry out a run without inking. Change the paper.
|
|
Cause
|
New or badly washed blanket that is too adherent.
|
|
Remedie
|
Wash the blanket correctly and apply talc.
|
|
Cause
|
Excessive pressure between the blanket cylinder andthe counter pressure cylinder.
|
|
Remedie
|
Adjust the pressure settings.
|
|
Cause
|
Ink too tacky.
|
|
Remedie
|
Reduce the tack with Anti Tack Compound (3 % max.).
|
|
Cause
|
Non uniform water supply to blanket.
|
|
Remedie
|
Adjust the water meteringspeed settings.
|
|
Cause
|
Spalling of the paper coating by the fount solution.
|
|
Remedie
|
Change the paper. Slightly increase the dampening.
|
|
Cause
|
pH of the fount solution too acid.
|
|
Remedie
|
Adjust the pH of the fount solution > See « The fount solution ».
|
|
Cause
|
Irregular dampening.
|
|
Remedie
|
Increase the speed of the dampening tank roller.
|
|
Cause
|
Incorrect water / ink balance.
|
|
Remedie
|
Check the water / ink balance. Slightly reduce the alcohol level.
|
|
Cause
|
Ink too sticky.
|
|
Remedie
|
Soften the ink with Arctic Thinner 501 (3 % max.).
|
|
Cause
|
Irregular ink deposition.
|
|
Remedie
|
Incorrect imposition. Check the form roller movement. Adjust the pressure settings.
|
18. Phantom effect, reappearance of the previous print run or the print run underway but out of shift.
|
Cause
|
Worn blanket.
|
|
Remedie
|
Change the blanket. Even if the blanket seems to be clean, its compressible layer may be altered and the phantom image may appear later.
|
|
Cause
|
Form rollers incorrectly adjusted on inking rollers.
|
|
Remedie
|
Adjust the pressure settings of the form rollers on the inking rol- lers.
|
Send