Method and apparatus for laminating image-bearing media
AssigneePolaroid Corporation
InventorAlfredo G. Kniazzeh
Life of this patent
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Abstract
A laminating roll for laminating a layer of protective coating to an image-bearing layer, has a generally cylindrical metallic core and a generally cylindrical compliant and resilient covering surrounding the core. The core and covering both having positive crowns such that the diameter of the outer surfaces of the core and covering measured at central portions thereof are respectively greater than the diameters measured at end portions thereof. The differences between the diameters of the core at central and end portions of the core is greater than that of the covering. The thickness of the covering increases from the center to the ends of the roll.
Claims26
A method for use in a machine for laminating a layer to an image-bearing layer, the machine having a pair of laminating rolls for receiving the layers in a nip therebetween, and wherein one of the rolls has a core and an incompressible or nearly-incompressible compliant and resilient outer covering;
- the method of obtaining substantially uniform normal traction on the layers across the length of the rolls comprising the step of;
- using as said one roll a roll whose core and covering each have a positive crown in the central portions thereof and with the crown of the core being greater than the combination of the crown of the covering the core.
A laminating roll for laminating a layer of protective coating to an image-bearing layer, the roll comprising in combination a generally cylindrical rigid core and a generally cylindrical incompressible or nearly-incompressible compliant and resilient covering surrounding the core, the core and covering both having positive crowns such that the diameter of the outer surfaces of the core and covering measured at central portions thereof are respectively greater than the diameters measured at end portions thereof, and wherein the differences between the diameters of the core at central and end portions of the core is greater than that of the covering;
- and the thickness of the covering increasing from the center generally symmetrically towards the ends of the roll while nip width increases from the center to the ends of the roll so as to minimize the shear tractions in the protective coating and in the image bearing material while maintaining a uniform degree of lamination across the length of the roll.
In a machine for laminating a layer to an image-bearing layer, the machine including a pair of upper and lower rolls, laminating rolls for receiving the layers in a nip therebetween and wherein the lower roll has a hard core and an incompressible and nearly-incompressible compliant flexible and resilient outer covering;
- the improvement including positive crowns formed on both the outer surface of the core and covering of the upper roll such that the diameters of the core and covering diminish from a central portion to opposite ends of the core and covering and with the difference of the diameters measured between the central portion and opposite ends of the core being greater than that of the combination of the covering and the core.
A laminating roll for laminating a layer of protcctive coating to an image-bearing layer, the roll comprising in combination a generally cylindrical rigid core and a generally cylindrical and incompressible or nearly-incompressible compliant and resilient covering surrounding the core, the core and covering both having positive crowns such that the diameter of the outer surfaces of the core and covering measured at central portions thereof are respectively greater than the diameters measured at end portions thereof, and wherein the differences between the diameters of the core at central and end portions of the core is greater than that of the covering and the core;
- and the nip width is slightly narrower at the center of the rolls than at the ends of the rolls.
Dependencies are inferred from the claim text.