Patent ID: 7255918

Claim:
A coated paper sheets usable for on-demand-printing purposes using an offset press or an indirect drying electrophotographic printer, comprising: a paper sheet substrate and a coating layer formed on at least one surface of the sheet substrate by coating an aqueous dispersion liquid comprising, as principal components, a pigment and a binder, drying the coated liquid layer and smoothing the dried coating layer, and having a 75 degrees specular gloss of 70% or more, determined in accordance with TAPPI T480 om-92, wherein the paper sheet substrate is one surface-sizepressed, during a paper-forming procedure for the paper sheet substrate, with an aqueous sizepress liquid containg an anionic acrylic resin which comprises a copolymer of 50% by mass or more of acrylamide with 1 to 40% by mass of acrylonitrile and 1 to 20% by mass of at least one member selected from acrylic acid and methacrylic acid, in a dry solid amount of 0.5 to 3 g/m 2 and has a basis mass of 50 to 110 g/m 2 , wherein the coated paper sheet has an air permeance, and wherein the coated paper sheet exhibits, as a whole, (1) an air permeability of 4000 seconds or less, determined in accordance with JIS P 8117 using Type B testing device, (2) a Clark stiffness, in terms of a critical length L, of 12 cm or more, determined in a cross direction of the coated paper sheet in accordance with JIS P 8143 using a Clark stiffness tester and a specimen having a width of 30 mm, and (3) an internal bond strength of 200 mJ or more, determined in accordance with TAPPIUM 403.