Patent ID: 8361571

Claim:
A recording sheet, comprising: a paper substrate comprising a plurality of cellulosic fibers; and a composition, comprising: a water-soluble salt of a divalent metal; a complexing agent having an affinity for the divalent metal; and an optical brightening agent, wherein said complexing agent is selected from the group consisting of organic phosphonate, phosphate, carboxylic acid, dithiocarbamate, ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid salt, diethylenetriaminepentaacetic acid, diethylenetriaminepentaacetic acid salt, diethylene-triamine-pentamethylene phosphonic acid, diethylene-triaminepentamethylene phosphonic acid salt, crown ether, ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid disodium salt, ethylenediaminetetraacetic acid tetrasodium salt, ethylenediaminetetraacetic acid trisodium salt, ethylenediaminetetraacetic acid disodium magnesium salt, ethylenediaminetetraacetic acid disodium calcium salt, ethylenediaminetetraacetic acid diammonium salt, ethylenediaminetetraacetic acid dipotassium salt, ethylenediaminetetraacetic acid tripotassium salt, ethylenediaminetetraacetic acid dilithium salt, ethylenediaminetetraacetic acid tetramethylammonium salt, ethylenediaminetetraacetic acid calcium salt, ethylenediaminetetraacetic acid magnesium salt, ethylenediaminetetraacetic acid aluminum salt, polyacrylic acid, polyacrylic acid salt, polysorbate, poly-4-styrene sulfonic acid salt, glycerol formal, formamidinesulinic acid, sodium hypophosphite, potassium hypophosphite, calcium hypophosphite, organic phosphonate, organic phosphate, dithiocarbamate, sorbitol, sorbic acid, cellulose ether, ionic liquids, 1-butyl-3-methyl-imidazolium-thiocyanate, alkyl imidazoliums 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium methyl sulfate, methyl imidazolium, salts thereof, or a combination thereof.