Printing roller with polymeric coner and method of making the same

DETAILED DESCRIPTION The present invention overcomes the disadvantages of prior art devices by providing rollers and covers made of several different materials, taking advantage of the best features of each.
The result is a roller with cleanability and chemical resistance characteristic of the polymeric cover but one that is soft, permanent, and has the good driving characteristics of the underlying core.
The rollers require very little maintenance, will not change size and will stay set.
The non-porous surfaces will not absorb ink, water, or solvent and will not glaze, swell or shrink, but at the same time, washing the surfaces clean is faster, easier and requires less solvent than rubber.
While rubber rollers tend to absorb solvents and vehicles from the ink, thereby causing premature drying, the rollers of the present invention having a non-absorbent surface, are able to print longer as the inks stay fresher.
The polymeric surface develops an electrostatic charge as the presses run and this charge helps retain ink particles, keeping them from becoming airborn.
There is more uniform ink transfer because the surface accepts ink more readily and uniformly than rubber, and because it does not glaze or change, its uniformity will not change.
A major source of hickeys is eliminated because the roller surface cannot disintegrate or pull apart, and as the press runs, small dings will heal themselves.
These advantages are the result of the present invention in which a core is covered by a tough, thermoplastic, heat-shrinkable tubing.
The tubing contains a layer of tack-free adhesive on its inner surface.
To enhance the adhesion between the tubing and the adhesive, the inner surface of the tubing may be mechanically abraded or chemically etched or both prior to the application of the adhesive.
An extra advantage of using a tack-free adhesive is that the preformed tubing and adhesive system may be stored for several months without the loss of adhesive qualities.
Handling characteristics in both shipping and in applying the tubing to the roller are thus enhanced