Printing and like rollers

Claim 2

A roller for applying varnish, lacquer, ink and the like to sheet material, the roller comprising a magnetic cylindrical former, and a cover which is applied to the curved surface of the former and is magnetically retained thereon, the cover comprising a hollow cylindrical casting having an inside diameter equal to the outside diameter of the former and comprising an outer layer made from a castable material which is selected from the group comprising liquid polymeric systems and liquid prepolymeric systems capable of forming macromolecular structures having elastomeric properties and an inner layer made from a material which is selected from said group, which is capable of bonding with the outer layer and which has particles of a magnetic material dispersed therein.

Claim 3

A cover intended to be wrapped around the curved surface of a magnetic cylindrical former to produce a roller for use in applying varnish, lacquer, ink and the like, to sheet material, the cover being in the form of a hollow cylindrical casting having an inside diameter equal to the outside diameter of the former on which it is to be used, and comprising an outer layer made from a castable material which is selected from the group comprising liquid polymeric systems and liquid prepolymeric systems capable of forming macromolecular structures having elastomeric properties and an inner layer made from a castable material which is selected from said group which is capable of bonding with the outer layer and which has particles of a magnetic material dispersed therein.

Claim 4

A cover intended to be wrapped around the curved surface of a magnetic cylindrical former to produce a roller for use in applying varnish, lacquer, ink and the like, to sheet material, the cover being in the form of a hollow cylindrical casting having an inside diameter equal to the outside diameter of the former on which it is to be used, and comprising an outer layer made from a castable material which is selected from the group comprising liquid polymeric systems and liquid prepolymeric systems capable of forming macromolecular structures having elastomeric properties and an inner layer made from a castable material which is selected from said group which is capable of bonding with the outer layer and which has particles of a magnetic material dispersed therein.

Claim 5

A cover as claimed in claim 2, wherein the said polymeric material is a polyurethane having the following composition: 1. Urethane prepolymer 2. Filler 3. Plasticizer or diluent compatible with urethane 4. Urethane crosslinking and chain extending agent 5. Catalyst

Claim 6

A cover as claimed in claim 3, wherein the polyurethane material is of the following compositions: ______________________________________ CYANAPRENE A-9 (N=C=O=4.2) 100 parts silica (particle size of 60 parts 7 microns) dipropylene glycol diben- 65 parts zoate trimethylolpropane 4.28 parts triethylenediamine 3 parts per hundred of Trimethylol- propane ______________________________________

Claim 7

A cover as claimed in claim 2, wherein the outer layer of the cover is of approximately 0.350 inches in thickness and the inner layer is of approximately 0.070 inches in thickness.