One of the most frequently encountered problems with essentially all rubber rollers that are available to date is that of shrinkage, and as the rollers shrink and change in diameter they require resetting.  As rollers shrink they also harden, glaze over, and begin wearing or pitting.

The basic cause for rollers shrinking or changing in size is extremely simple.  Roller coverings are made from synthetic rubber, and to achieve the required softness for inking and dampening rollers, a considerable amount of additives referred to as plasticizers must be incorporated into the rubber formulation.  On the press the rubber covering is exposed to various chemicals in the form of inks, roller washes and fountain solutions, all of which attack the rubber.  These chemicals tend to leach the plasticizer additives out of the rubber and the result is like wringing water out of a sponge!  When the plasticizers are removed from the rubber, the rubber shrinks in size thus becomes harder!  This attack may occur over weeks or months, depending on factors such as the type of inks or roller washes being used, the frequency of exposure to wash-ups, and in general how well the rollers are maintained.  A major factor is in the quality of the rubber covering itself.

The need for more stable roller coverings has been brought on in part by changes imposed upon the industry through legislation, the impact of which has had a major effect  on pressroom chemistry.  While the pressroom workplace may have become a safer environment, these changes have resulted in chemistry which is far more aggressive on rubber covered rollers.  Another factor leading to the requirement of more stable roller coverings is that today’s printing equipment is far more demanding, generally operating at higher speeds and to more exacting tolerances.

As changes in pressroom chemistry have occurred over the last ten years there have been advancements to rubber technology, but not enough to keep place with today’s requirements.  There remains a need for an ultra stable rubber covering, one which will run without those frequent on press adjustments, one that holds its dimensions and does not keep shrinking until it is totally out of tolerance, one which holds its hardness, and one that resists wear!