Patent ID: 8038781

Claim:
An ink composition comprising: a colorant represented by the following formula (I); water; a guanidine-based compound; and a colorless water-soluble planar compound having more than ten delocalized π-electrons within one molecule: wherein, M represents a hydrogen atom, a metal atom, an oxide thereof, a hydroxide thereof or a halide thereof; k, l, m and n represent an integer of 0≦k≦8, an integer of0≦1≦8, an integer of 0≦m≦8and an integer of0≦n≦8, respectively, provided that k, l, m and n satisfy 4≦k+1+m+n≦8; each of X 1 , X 2 , X 3 and X 4 represents a substituent selected from the group consisting of —SO—R 1 , —S0 2 —R 1 , —SO 2 NR 2 R 3 , —CONR 2 R 3 , —CO 2 —R 1 , —CO—R 1 , a sulfo group and a salt thereof, a carboxyl group and a salt thereof, and a phosphono group and a salt thereof, provided that at least one of X 1 , X 2 , X 3 and X 4 has an ionic hydrophilic group as a substituent; R 1 represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group; R 2 represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group; R 3 represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group; and Pc represents a (k+l+m+n)-valent phthalocyanine nucleus represented by the following formula (II); wherein each of the four benzene rings A, B, C and D has at least one of X 1 , X 2 , X 3 and X 4 ; and Y 1 , Y 2 , Y 3 , Y 4 , Y 5 , Y 6 , Y 7 and Y 8 each independently represents a hydrogen atom or a monovalent substituent which may further have a substituent.