Roller care and maintenance
Taking proper care of your inking and dampening rollers is extremely important as they are responsible for laying the ink down evenly and smoothly to the plate to give you the highest quality print. Unigraph has a full selection of high quality products to assist you in keeping your rollers in top condition.
Following are some guidelines for the care and maintenance of rollers.
A good roller should have a soft, velvety feel to it with a durometer between 25 and 32 (especially form rollers).
Once a roller has a durometer over 35, it no longer has the ability to lay the ink down smoothly and evenly and should be replaced.
Regular use of Uni O.D Deglazer will help keep the durometer of the rubber in the desirable range and increase the life of your rollers.
One of Unigraph’s water-miscible washes should be used for your regular wash-ups with water always being used toward the end to assure that the surfactants and other water-miscible particles are removed from the rollers.
Roller settings should be checked on a regular basis. A quick check each month would be advisable as it is normal for rollers to shrink somewhat during their usable life.
A good quality roller will shrink a little early in its lifespan, then very gradually change over the longer term.
Good quality, well maintained rollers can be expected to last two years or more.
Check press manufacturer’s recommendations for roller settings and in all cases keep the settings as light as possible as there is no positive side to a heavier setting.
Heavier settings will create more heat in the ink train and cause rollers to deteriorate quickly.
They can also cause deflection in the rollers which will give you an uneven stripe on the distributor roller and have the roller touching the plate in some areas and not others.
Colour inconsistency may also be experienced as the heavier settings may not allow the ink to flow evenly and consistently through the nip of the rollers.
Form rollers should be checked for side play as any sideways movement in the rollers can cause premature glazing as well as negative effects on print quality, some slurring of the dots and tinting or toning on the printed sheet.
Make sure that new form rollers are shimmed and fitted properly to prevent any sideways movement.
If form rollers are purposely allowed to move sideways from time to time to combat a ghosting problem, never allow the last form roller (usually #4) to oscillate as this is a clean-up roller. Also assure that the rollers are locked up properly again after the ghosting form is completed to prevent wear in the journals and glazing of the rollers.
Poorly maintained rollers are a major cause of poor print quality. Assure that this is not the case in your shop and make Unigraph products a part of your regular roller care.
