Thermal roll sleeve with a copper alloy are obtained by

Thermal roll sleeve with a copper alloy are obtained by variation of temperature.

The thermal rolls of print media of this invention comprise a core/spindle and a sheet, preferably continuous, of a print medium of substantially the same width as the core/spindle. The sheet of print medium is wound around the core/spindle to provide a thickness of layered paper on the core/spindle of at least one half inch, measured from the periphery of the core/spindle to the outer layer of the sheet of print medium on the roll. At least one side of the wound sheet of print medium is marked with at least one impression which serves as an identifying mark. The “sides” of the roll of a print medium, as referred to herein, are where the edges of the wound print medium are exposed. The term “impression” as used herein includes shallow indentations as well as realignment of the edges of the wound print medium and realignment of the fibers within the wound print medium. In realigning the edges and/or fibers of the wound print medium, there may be no indentation which is detectable and in certain embodiments, no indentation at all.

Thermal paper rolls in the past...