b) obtain new color separation for pressroom conditions;
c) establish standard procedures for all operators
3. Consult ink manufacturer
4. Printer’s customer, printer and ink manufacturer must all use same formula guide for exact matches
a) check air systems for circulation of dust.
b) vacuum overhead fixtures.
c) hang plastic sheeting over press.
d) use less spray powder.
NOTE : Properly maintained “hickie-picker” rollers do work. All require frequent scrubbing for optimum performance.
NOTE : Properly maintained “hickie-picker” rollers do work. All require frequent scrubbing for optimum performance.
1. Ink is thixotropic.
2. Build up of Micro-Foam.
1. Add 1-3% of transfer agent or up to 5% reducer.
2. Check for excessive fall of return ink in chambered anilox press. Add 0.4-0.8% of a non-silicone defoamer.
3. Adjust pump speed
1. Incorrect selection of pigments to be UV aqueous coated. True dye-based pigment can/will bleed when coated.
1. Select pigments that are coatable.
1. Printing unit dirty.
2. Variation in the anilox.
3. Variation in the plates.
4. Changes in substrate.
1. Clean unit and put fresh ink.
2. Change anilox.
3. Remake plate.
4. Select a different substrate or size the sheet.
1.Too much impression pressure.
2. Plate too soft.
3. Contaminated ink.
4. Particles in ink.
5. Too coarse anilox/screen ratio.
1. Reduce the amount of impression.
2. Use a harder plate.
3. Thoroughly clean the unit and replace with new ink.
4. Thoroughly clean the unit and replace with fresh ink, Determine the source of particles.
5. Change to a finer anilox/screen ratio.
1. Mechanical in origin.
2. Too hard of a sticky back.
1. Repair press if possible.
2.Swift to a softer sticky back.
1. Dyne level (of substrate) is too low. Low dyne level can adversely affect transfer.
2. A plasticizer and/or contaminate is on the surface of the stock.
3. Ink and/or coating crosslink density is too high = brittle.
4. Ink is not properly cured; crosslink density is too low.
5. The treatment/coating on the stock is faulty.
1. Corona or flame treat the stock or select a substrate with higher dyne level 38+.
2. Adjust slip agent/surfactant.
3. Use lower crosslink density formulation. Decrese lamp settings speed.
4. Decrease the press speed. Reducing the lamp setting, and increasing the press speed will make the cure worse.
5. Select another stock or possibly apply a primer.
1. The ink is not properly cured. It is only cured at the surface and it is breaking off at the dry/wet ink interface and building up on the next units. Though the ink will be cured and at proper densities at the end if the press.
1. Check the UV lamps for adequate energy. Select a higher line anilox to lower the film thickness. If the film thickness is too high the UV light will not be able to penetrate to cure the ink thoroughly. Add photoinitiator 1% at a time up to a maximum of 3%.
2. Reduce press speed.
3. If the printer already has their lamps on high, and they do not have the ability to go to a finer line anilox or thinner ink film, the next step should be to reduce the press speed.
1. The ink is surface curing too much, or not receiving proper through cure.
2. The ink film thickness is too high. Not allowing the UV energy to properly penetrate the film and thoroughly cure the ink. This is especially evident in blacks and dark colors.
3. UV lamps may not be providing adequate energy because of old bulbs, dirty reflectors, focal plane has become off standard.
4. Ink formulation is not allowing for enough crosslink density.
5. Substrate absorbs too quickly, causing a lack of binding.
1. Add photoinitiator 1% at a time up to a maximum of 3%.
2. Use a finer line anilox.
3. Check the lamp age and make sure that the reflectors are clean and check the focal plane. check the lamp output. If all ok, reduce press speed.
4. Reformulate the ink with faster, better cross-linking raw materials.
5. consider using a size coat or a different stock.
1. UV lamps may not be providing adequate energy because of old bulb is out of adjustment.
2. The UV unit may not be providing adequate energy.
3. The ink film thickness is too high. Not allowing the UV energy to properly penetrate the film and thoroughly cure the ink.
4. The ink formulation may not be fast enough for the available energy.
5. Excessive absorption into the stock.
1. Check the lamp age and make sure that the reflectors are clean and check the focal plane. Check the lamp output. if ok, reduce press speed.
2. Make sure the UV unit is functioning properly.
3. Use a finer line anilox and/or weaken the ink.
4. Add a photoinitiator1%at a time up to maximum of 3%.
5. a. try raising ink viscosity first. b. select a different stock or prime the stock
1. Worn Doctor Blade.
2. Improperly set Doctor Blade.
3. Worn or damaged anilox.
4. Particles in ink.
1. Replace Doctor Blade.
2. Reset Doctor Blade.
3. Replace Anilox
4. Thoroughly clean unit and replace with fresh ink. Determine the source of particles.
1. Stock has a non-uniform surface.
2. Treatment on the film is not uniform.
3. Place Durometer and thickness.
4. Variation in the plate.
5. Sticky-back cushion and thickness.
6. Worn anilox.
1. Use a better grade of substrate. Apply a size to heal the stock. Usean opaque ink or an ink with better holdout.
2. Select another stock, Corona treat in-line. Apply a size/primer to the stock.
3. Check the Durometer and thickness of the plate.
4. Check the plate. Remake if necessary.
5. Check sticky-back cushion and thickness.
6. Check the condition of the anilox. Replace the anilox.
1. Variation in the plate.
2. Contaminated ink.
3. Printing over inks that contain silicone.
4. build up of Micro-Foam.
5. Voids in Substrate.
6. Surface tension of the stock is too low.
1. Check the plate. Remake if necessary.
2. Thoroughly clean out the unit. Replace with fresh ink.
3. Use silicone free inks.
4. Check for excessive fall of return ink in chambered anilox press. Add 0.4%-0.8% of a non-silicone defoamer. Adjust pump pressure.
5. Put down a size or use a different substrate.
6. Corona or flame treat the substrate.
1. The paper is rough and abrasive.
2. The ink is not properly cured.
3. UV lamps may not be providing adequate energy because of old bulbs, dirty reflectors, the bulb is out of adjustment.
4. The ink film thickness is too high, especially in blacks, for amount of UV energy.
1. Obtain smoother stock or apply a size to smooth the sheet.
2. Add photoinitiator 1% at a time up to maximum 3%.
3. Check the lamp age and make sure that the reflectors are clean and check the focal plane. Check the lamp output.
4. It may be necessary to double hit (bump) the ink.