Abstract: The invention relates to a printing method by an offset printing press and an offset printing press by which a substrate process is carried out for low-whiteness printing paper such as paper for newspaper with aqueous substrate treatment agent so that the print quality can be improved. In the invention, in order to suppress occurrence of a curl of printing paper, substrate treatment agent containing solid fine particles and a binder component is supplied to a printing face of printing paper, and the substrate treatment agent is dried to form a porous layer having a great number of holes having a smaller diameter than that of pigment contained in printing ink from the solid fine particles and the binder resin. Then, offset printing is carried out on the printing paper.

Abstract: The present invention relates to a printing method by an offset printing press and an offset printing press and has an object to carry out a substrate process for low-whiteness printing paper such as paper for newspaper with substrate treatment agent and to enhance the print quality while preventing appearance of muddiness in printing ink by the substrate treatment agent. The present invention is configured such that substrate treatment agent such as low-whiteness enhancement agent is supplied to a printing face of printing paper, and thereafter the substrate treatment agent supplied to the printing face is dried and then offset printing is carried out for the printing paper by a printing apparatus.

Abstract: A printing method by an offset printing press and an offset printing press are disclosed which suppress occurrence of curl with printing paper while making it possible to improve the printing quality by performing a ground process with aqueous ground processing material for low whiteness printing paper such as newsprint paper. To a printing face of the printing paper, aqueous ground processing material is supplied. At the same time with or later than the supply of the ground processing material, moisture is supplied to a reverse face to the printing face of the printing paper. Thereafter, offset printing is performed for the printing paper.