Rubber rollers are manufactured with a texured surface which is produced by a spinning grinder wheel.
The the hills and valleys of the textured surface is what provides the grip/surface that allows ink to adhere to and flow from roll to roll thoughout the ink train.
When the roller’s ‘valleys’ become plugged, the rollers surface becomes smooth to where ink does not adhere properly.
To check rollers condition, use your sense of sight and touch.
Soft rollers should have a dull, satin surface appearance, and exhibit a marked resistance to the drag of your fingers as you drag them accross the rollers’ suface.
If rollers have a smooth slick feel to the drag of your fingers and look glassy, they are glazed.
When rollers glaze, the textured ground surface does not hold and transfer ink effectively, forcing you to run more (thicker ink films) ink and water to achive required ink densities.
Thicker ink films result in dot gain, hickies, mottled solids, ink drying problems, and most likely increased spoilage and waste.
There are several types of glaze that effect roller performance.
Paper lint, gum, ink vehicle and pigment residue, and calcium carbonate, and each requires cleaning to effectively remove them.
If you use a good quality water misible roller wash (one that mixes well in ‘warm’ water and stays in suspension) you will remove most all paper, ink, and chemical glaze. In addition, if you use a good deglazer/desensitizer (like Varn Revitol) at least weekly, you will keep your rollers in clean and in good operating condition.
Roller cleaning sequence should go like this;
* Remove ink with a good waster misible roller wash followed up with a water/15%Vinegar-rinse that is warm or at room temperature.
*weekly, follow up water misible wash with applications of Varn Revitol.
Re-apply until revitol does not change color, then follow up Revitol with application of water/15%Vinegar-rinse to all remove traces and neutralize alkali PH of Revitol and condition ink rollers to become ‘more’ ink receptive.