Radiation-curable ink composition and image recording method

An ink set of a radiation-curable ink composition comprising a magenta ink containing a dye represented by the general formula (I–1), and a cyan ink containing a dye represented by the general formula (A-I), wherein the radiation-curable ink composition comprises a monomer having a polymerizable group selected from the group consisting of an acryloyl group, a methacryloyl group, an allyl group, and a vinyl group, an oil-soluble dye, and from 0.005 to 1% by weight of a storage stabilizer, wherein the oil-soluble dye is dissolved in the ink,

• wherein the general formula (I–1) is represented by
• wherein D-N= represents an atomic group necessary such that the compound represented by the general formula (I–1) absorbs light in a visible region and/or in a near infrared region, and D represents a five-membered heterocyclic group represented by the following general formulae (a), (b), (c), (d) or (f);
• wherein R5 and R6 each independently represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group;
• R1, R2, R4, R7 to R13, and R18 to R20 each independently represents a hydrogen atom or a substituent group;
• and R1 and R2, R1 and R5, and R5 and R6 may optionally form a ring by combining with each other;
• and
• wherein the general formula (A-I) is represented by
• wherein X1, X2, X3, and X4 each independently represents a group selected from —SO-Z, —SO2-Z, —SO2NR1R2, —CONR1R2, —CO2R1, and a sulfo group;
• Z represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group;
• R1 and R2 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, provided that R1 and R2 do not represent a hydrogen atom at the same time;
• M represents a hydrogen atom, a metal element, a metal oxide, a metal hydroxide, or a metal halide;
• Y1, Y2, Y3, and Y4 each independently represents a hydrogen atom or a monovalent substituent;
• and a1 to a4 and b1 to b4 represent the numbers of X1 to X4 and Y1 to Y4, respectively and each independently represents an integer of from 0 to 4, provided that the total sum of a1 to a4 is 2 or more and 16 or less.

A radiation-curable ink composition comprising a monomer having a polymerizable group selected from the group consisting of an acryloyl group, a methacryloyl group, an allyl group, and a vinyl group, an oil-soluble dye, and from 0.005 to 1% by weight of a storage stabilizer, wherein the oil-soluble dye is dissolved in the ink, wherein the oil-soluble dye is at least one member selected from dyes represented by the following general formula (I–1):

• wherein D-N= represents an atomic group necessary such that the compound represented by the general formula (I–1) absorbs light in a visible region and/or in a near infrared region, and D represents a five-membered heterocyclic group represented by the following general formulae (a), (b), (c), (d) or (f);
• wherein R5 and R6 each independently represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group;
• R1, R2, R4, R7 to R13, and R18 to R20 each independently represents a hydrogen atom or a substituent group;
• and R1 and R2, R1 and R5, and R5 and R6 may optionally form a ring by combining with each other;
• and
• dyes represented by the following general formula (A-I):
• wherein X1, X2, X3, and X4 each independently represents a group selected from —SO-Z, —SO2-Z, —SO2NR1R2, —CONR1R2, —CO2R2, and a sulfo group;
• Z represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group;
• R1 and R2 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, provided that R1 and R2 do not represent a hydrogen atom at the same time;
• M represents a hydrogen atom, a metal element, a metal oxide, a metal hydroxide, or a metal halide;
• Y1, Y2, Y3, and Y4 each independently represents a hydrogen atom or a monovalent substituent;
• and a1 to a4 and b1 to b4 represent the numbers of X1 to X4 and Y1 to Y4, respectively and each independently represents an integer of from 0 to 4, provided that the total sum of a1 to a4 is 2 or more and 16 or less.