RECORDING MEDIUM HAVING THERMOCHROMISM

PROBLEM TO BE SOLVED: To obtain indicator function or forgery preventing function by a method wherein layers, in which reversible thermochromism element and irreversible thermochromism element are dispersed into fixing agent, are provided on the surface of bearers having different discoloring points mutually while the discoloration of irreversible thermochromism element due to the change of temperature is recorded as the thermal history of the change of condition. SOLUTION: A recording medium having thermochromism is constituted of an irreversible thermochromism layer 4, laminated on a reversible thermochromism layer 3 formed on the surface of a bearer 2, while both layers are provided with mutually different discoloring points whereby the change of condition can be recorded as a thermal history by the discoloring of the irreversible thermochromism layer 4 due to the change of temperature. In this case, the recording medium is a thermochromism recording medium, in which the composite effect of functions of respective elements is developed effectively. Such a composite thermochromism is provided with not only both of temperature showing function, possessed by the reversible thermochromism, and recording or history indicating functions of the irreversible thermochromism but also the reversible function can be omitted or changed in accordance with necessity. The recording medium having thermochromism is very effective as a means for preventing the modification or forgery of the recording medium.