Aqueous ink composition
AssigneeRicoh Company, Ltd.
InventorsKakuji Murakami, Masaru Shimada, Tamotsu Aruga, Hiroyuki Uemura, Kiyofumi Nagai
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AssigneeRicoh Company, Ltd.
InventorsKakuji Murakami, Masaru Shimada, Tamotsu Aruga, Hiroyuki Uemura, Kiyofumi Nagai
Estimating the term…
An aqueous ink composition comprises (a) a dye having formula (I) in an amount of 0.5 to 6.0 wt. %, in which 20% or more of the total of the cations of --SO.sub.3 X and --OX groups directly connected to the aromatic rings thereof is replaced by Li.sup.+ ion or a quaternary ammonium ion, ##STR1## wherein X represents a cation; R.sup.1 represents hydrogen, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, or an amino group; R.sup.2 represents ##STR2## (in which R.sup.5 and R.sup.6 each represent hydrogen, an alkyl group having 1 to 4 carbon atoms, a hydroxyethyl group, or a cyanoethyl group); R.sup.3 represents hydrogen, --SO.sub.3 X; R.sup.4 represents hydrogen, or a --C.sub.2 H.sub.4 OX, (b) a polyhydric alcohol in an amount of at least 10 wt. %; and (c) water.
An aqueous ink composition comprising:
Dependencies are inferred from the claim text.