Yamada Chemical Co., Ltd.

Yutaka Muraki

Katsuhiko Tsunemitsu

Hajime Kawai

Hidekazu Ishida

The present invention provides a novel phthalide compound represented by the following formula, which rapidly forms blue-blue black color with a developer when it is used as a recording material and, since a color image formed therewith has an intense absorption at 700.about.50 nm, it is usable for optical character reader; ##STR1## where R.sup.1 and R.sup.2 represent, independently, alkyl group having 6 or less carbon atoms; cycloalkyl group having 5 or 6 carbon atoms; aryl group; or heterocyclic ring connecting R.sup.1, R.sup.2 and N, R.sup.3 and R.sup.4 represent, independently, alkyl group having 6 or less carbon atoms; cycloalkyl group having 5 or 6 carbon atoms; aryl group; a heterocyclic ring connecting R.sup.3, R.sup.4 and N, X.sup.1 .about.X.sup.3 represent, independently, hydrogen atom, alkyl group having 6 or less carbon atoms, alkoxy group having 6 or less carbon atom or halogen atom, X.sup.4 represents hydrogen atom, alkyl group having 6 or less carbon atoms, alkoxy group having 6 or less carbon atom, halogen atom or ##STR2##

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Uji, Japan

Yutaka Muraki