Record receiver having plural interactive leaves or a colorless color former, method of use, or developer therefor

SECTION I - CLASS DEFINITION

Material which is used to form a visible record by a reactive or interactive, usually chemical or physico-chemical, phenomenon or a method of using such a material to form a record. The formation phenomenon is one of the following: (a) The chemical decomposition of a colorless substance to form a substance having color; (b) the chemical combination of two or more colorless chemical moieties to produce a substance having color; (c) The further chemical change of (a) or (b) above, to form a color different from an original color; and (d) The chemical or physico-chemical complementarity between the bottom surface of one sheet of a record receiver and the top surface of an adjacent sheet with which the first sheet id associated.

Generally, the phenomenon in cases (a) through (d) is thought about by the application to the record receiver of heat and/or pressure in the areas to be "marked".