Patent ID: 8283005

Claim:
An inkjet recording medium comprising, on a substrate, an ink-receiving layer comprising inorganic fine particles and an organic nitrogen-containing cationic polyurethane, the organic nitrogen-containing cationic polyurethane being contained in a greater quantity in a half of the ink-receiving layer at a side nearer to the substrate (a near-substrate side) than in a half of the ink-receiving layer at a side further from the substrate (a far-substrate side) when the ink-receiving layer is divided into two equal parts by a plane parallel to the substrate, wherein the ink-receiving layer has two or more constituent layers and an uppermost constituent layer lying furthest from the substrate has a thickness of from 0.05 μm to 5 μm and contains colloidal silica, wherein the ink-receiving layer further comprises a sulfur compound selected from the group consisting of a thioether compound, a thiourea compound, a disulfide compound, a sulfinic acid compound, a thiocyanic acid compound, a sulfur-containing heterocyclic compound, and a sulfoxide compound, the thioether compound being a compound represented by the following formula (1): R 1 —(S—R 3 ) m —S—R 2 (1) wherein, in formula (1), R 1 and R 2 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or an alkyl- or aryl-containing group, R 1 and R 2 may combine with each other to form a ring, provided that at least either R 1 or R 2 represents an alkyl group substituted with an hydrophilic group or a basic nitrogen-containing group; R 3 represents an alkylene group which may be substituted and which may have an oxygen atom; m represents an integer of 0 to 10, and when m is 1 or more, at least one sulfur atom bound to R 3 may be a sulfoxide group or a sulfonyl group; the thiourea compound being a compound having at least one structural unit represented by >N—C(═S)—N< per molecule; the disulfide compound being a compound represented by the following formula: R 1 —S—S—R 2 wherein, in the formula, R 1 and R 2 each independently represents an organic group containing a carbon or nitrogen atom bound to the disulfide sulfur; the sulfinic acid compound being a compound represented by the following formula: R—SO 2 M wherein, in the formula, R represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a polymer residue; and M represents a hydrogen atom, an alkali metal atom or an ammonium.