Method of determining the age of ink having time d

专利名称：Method of determining the age of ink having

time dependent characteristics

发明人：Thomas H. Frey,Isaiah Lieberman申请号：US08/5042申请日：19950720公开号：US05600443A公开日：19970204

摘要：A method and ink composition are disclosed that utilize two mechanisms for thepurpose of indicating the approximate age of an ink that has been deposited on a writingsurface. The first mechanism relates to detecting color shifts of pH sensitive compoundsin the ink as the result of the evaporation of certain acidic or basic chemicals thereof. Thesecond mechanism relates to the oxidation of compounds in the ink. Spectroscopicallygenerated curves are plotted as the ratio of reactants to products, versus time. Thespectral characteristics of the ink are determined in units of percent reflectance of theactive compounds in the ink so that the age of the ink can be computed by reference toknown reaction rates. A plurality of dyes having differing reaction rates may be added tothe ink to enable precise measurements to be made over different time intervals.

申请人：SIGNA SCAN, INC.

代理人：Morland C. Fischer

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