Patent ID: 7846516
Filing Date: 2010-12-07
Classification: B41M

Abstract:
1. An ink jet recording medium comprising a substrate and an ink receiving layer provided with at least an upper layer and a lower layer formed on said substrate, wherein said upper layer: (A) constitutes the outermost layer of said ink receiving layer; (B) contains none of a polyallylamine hydrochloride, a methyldiallylamine hydrochloride polymer and a diallylamine hydrochloride-sulfur dioxide copolymer; and (C) contains inorganic pigment particles, a binder and an alkylsulfonic acid of which the alkyl group is a straight or branched unsubstituted alkyl group having 1 to 4 carbon atoms; and said lower layer: (D) is a layer lying just under said upper layer; and (E) contains at least one cationic polymer selected from the group consisting of a polyallylamine hydrochloride, a methyldiallylamine hydrochloride polymer and a diallylamine hydrochloride-sulfur dioxide copolymer, inorganic pigment particles, a binder and an alkylsulfonic acid of which the alkyl group is a straight or branched unsubstituted alkyl group having 1 to 4 carbon atoms; wherein the ratio by mass of the cationic polymer contained in said lower layer to the inorganic pigment particles contained in said upper layer and lower layer, {(Cationic polymer)/(Inorganic pigment particles)×100}, is 0.1% or more and 1% or less; and wherein the ratio by mass of the alkylsulfonic acid to said inorganic pigment particles contained in said upper layer and lower layer, {(Alkylsulfonic acid)/(Inorganic pigment particles)×100}, is 1.4% or more and 2.1% or less.