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US 4,309,255 AGranted
Electrochromic recording paper
AssigneeInternational Business Machines Corporation
InventorsPaul L. Gendler, Barbara D. Grant, Clinton D. Snyder
Life of this patent
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Abstract
A medium for electrochromic recording is provided by treating paper with a water soluble leuco methylene blue compound having the formula ##STR1## wherein R is a sulfonated aromatic or sulfonated aliphatic moiety.
Claims3
A substrate for use in electrochromic recording comprising paper containing a water soluble leuco methylene blue compound which is a salt of 3,7-bis-(dimethylamino)-10-(2-sulfobenzoyl)-phenothiazine.
Dependencies are inferred from the claim text.